[Qemu-devel] Floating point unit bugs

[Qemu-devel] Floating point unit bugs

[G 3]

I made a diagnostic program for the floating point unit. It will test  
various PowerPC floating point instructions for compatibility with  
the PowerPC G3 processor. It was tested on a PowerPC G3 and G5  
system. The results of the program in qemu-system-ppc were pretty  
bad. About every instruction tested is not implemented correctly.

Here is the download link to the program: http://www.mediafire.com/ 
file/6j9tqubvk73lkw1/floating_point_test_program.zip

Here is the full source code to the program:
/ 
************************************************************************ 
**************
  * File: main.c
  * Date: 4-30-2017
  * Description: Implement a test program for various floating point  
instructions.
  * Note: tests made to work with PowerPC G3 and G5 only.
  * Compiling on Mac OS X: use gcc-3.3 -force_cpusubtype_ALL
  * Note: fsqrt test will not work on PowerPC G3.
   
************************************************************************ 
**************/

#include <stdio.h>
#include <stdint.h>
#include <math.h>
#include <float.h>
#include <inttypes.h>

// Used to convert unsigned integer <--> double
union Converter
{
     double d;
     uint64_t i;
};

typedef union Converter Converter;

/* Describes the name and description of each bit of the FPSCR */
struct fpscr_info
{
     char name[8];
     char description[100];
};

struct fpscr_info finfo[] =
{
     "FX", "Floating-point exception summary",
     "FEX", "Floating-point enabled exception summary",
     "VX", "Floating-point invalid operation exception summary",
     "OX", "Floating-point overflow exception",
     "UX", "Floating-point underflow exception",
     "ZX", "Floating-point zero divide exception",
     "XX", "Floating-point inexact exception",
     "VXSNAN", "Floating-point invalid operation exception for SNaN",
     "VXISI", "Floating-point invalid operation exception for ∞ - ∞",
     "VXIDI", "Floating-point invalid operation exception for ∞/∞",
     "VXZDZ", "Floating-point invalid operation exception for 0/0",
     "VXIMZ", "Floating-point invalid operation exception for ∞ * 0",
     "VXVC", "Floating-point invalid operation exception for invalid  
compare",
     "FR", "Floating-point fraction rounded",
     "FI", "Floating-point fraction inexact",
     "FPRF", "Floating-point result class descriptor ",
     "FPRF", "Floating-point less than or negative",
     "FPRF", "Floating-point greater than or positive",
     "FPRF", "Floating-point equal or zero",
     "FPRF", "Floating-point unordered or NaN",
     "NO NAME", "Reserved - you shouldn't be seeing this",
     "VXSOFT", "Floating-point invalid operation exception for  
software request",
     "VXSQRT", "Floating-point invalid operation exception for  
invalid square root",
     "VXCVI", "Floating-point invalid operation exception for invalid  
integer convert",
     "VE", "Floating-point invalid operation exception enable",
     "OE", "IEEE floating-point overflow exception enable",
     "UE", "IEEE floating-point underflow exception enable",
     "ZE", "IEEE floating-point zero divide exception enable",
     "XE", "Floating-point inexact exception enable",
     "NI", "Floating-point non-IEEE mode",
     "RN", "Rounding bit 0",
     "RN", "Rounding bit 1",
};

// Prints all the FPSCR settings that are set in the input
void print_fpscr_settings(uint32_t fpscr)
{
     int i;
     for (i = 0; i < 32; i++) {
         if ((fpscr >> i) & 0x1 == 1) {
             /* right description = 31 - i  Oddity of IBM  
documentation */
             printf("bit %d: %s - %s\n", 31-i, finfo[31-i].name, finfo 
[31-i].description);
         }
     }
}


#define ZE 27
#define set_fpscr_bit(x) asm volatile ("mtfsb1 %0" : : "i"(x))

/* Keeps track of the number of tests that failed */
int failed_tests = 0;

// Reset the FPSCR
void reset_fpscr()
{
     asm volatile("mtfsb0 0");
     asm volatile("mtfsb0 1");
     asm volatile("mtfsb0 2");
     asm volatile("mtfsb0 3");
     asm volatile("mtfsb0 4");
     asm volatile("mtfsb0 5");
     asm volatile("mtfsb0 6");
     asm volatile("mtfsb0 7");
     asm volatile("mtfsb0 8");
     asm volatile("mtfsb0 9");
     asm volatile("mtfsb0 10");
     asm volatile("mtfsb0 11");
     asm volatile("mtfsb0 12");
     asm volatile("mtfsb0 13");
     asm volatile("mtfsb0 14");
     asm volatile("mtfsb0 15");
     asm volatile("mtfsb0 16");
     asm volatile("mtfsb0 17");
     asm volatile("mtfsb0 18");
     asm volatile("mtfsb0 19");
     asm volatile("mtfsb0 20");
     asm volatile("mtfsb0 21");
     asm volatile("mtfsb0 22");
     asm volatile("mtfsb0 23");
     asm volatile("mtfsb0 24");
     asm volatile("mtfsb0 25");
     asm volatile("mtfsb0 26");
     asm volatile("mtfsb0 27");
     asm volatile("mtfsb0 28");
     asm volatile("mtfsb0 29");
     asm volatile("mtfsb0 30");
     asm volatile("mtfsb0 31");

     /* Check if everything is alright */
     uint32_t fpscr;
     asm volatile("mffs f0");
     asm volatile("stfd f0, 40(r1)");
     asm volatile("lwz %0, 44(r1)" : "=r"(fpscr));
     if (fpscr != 0) {
         printf("Warning: fpscr not equal to zero: 0x%x\n", fpscr);
     }
}

/*
  * The action to take if a test fails
  * Input one: message string
  * Input two: actual fpscr value
  * Input three: expected fpscr value
  * Input four: actual answer
  * Input five: expected answer
  */
  void test_failed(const char *message, uint32_t actual_fpscr,  
uint32_t expected_fpscr,
                   uint64_t actual_answer, uint64_t expected_answer)
  {
     printf("%s\n", message);
     printf("expected answer: 0x%" PRIx64 "\n", expected_answer);
     printf("  actual answer: 0x%" PRIx64 "\n", actual_fpscr);
     printf("expected fpscr: 0x%x\n", expected_fpscr);
     printf("  actual fpscr: 0x%x\n", actual_fpscr);

     /* Only print FPSCR bits if there is a difference */
     if (actual_fpscr != expected_fpscr) {
         printf("\nactual FPSCR bits set:\n");
         print_fpscr_settings(actual_fpscr);
         printf("\nexpected FPSCR bits set:\n");
         print_fpscr_settings(expected_fpscr);
     }
     printf("\n");
     failed_tests++;
  }

/*
  * Returns the value of the FPSCR
  * output: unsigned 32 bit integer
  */
uint32_t get_fpscr()
{
     asm volatile("mffs f0");
     asm volatile("stfd f0, 40(r1)");
     uint32_t return_value;
     asm volatile("lwz %0, 44(r1)" : "=r"(return_value));
     return return_value;
}


/* The fpscr and answer have to be right for a test to pass. */


/* Test the fadd instruction */
void test_fadd()
{
     Converter c;
     uint64_t expected_answer = 0x3ff3333333333334;
     uint32_t actual_fpscr, expected_fpscr = 0x82064000;
     reset_fpscr();
     asm volatile("fadd %0, %1, %2" : "=f"(c.d) : "f"(0.4), "f"(0.8));
     actual_fpscr = get_fpscr();
     if (actual_fpscr == expected_fpscr && c.i == expected_answer) {
         printf("fadd test passed\n");
     } else {
         test_failed("fadd test failed", actual_fpscr,  
expected_fpscr, c.i, expected_answer);
     }
}

/* Test the fadds instruction */
void test_fadds()
{
     Converter c;
     uint64_t expected_answer = 0x407024d500000000;
     uint32_t actual_fpscr, expected_fpscr = 0x82064000;
     reset_fpscr();
     asm volatile("fadds %0, %1, %2" : "=f"(c.d) : "f"(257.445),  
"f"(0.857));
     actual_fpscr = get_fpscr();
     if (actual_fpscr == expected_fpscr && c.i == expected_answer) {
         printf("fadds test passed\n");
     } else {
         test_failed("fadds test failed", actual_fpscr,  
expected_fpscr, c.i, expected_answer);
     }
}

/* Test the fsub instruction */
void test_fsub()
{
     Converter c;
     uint64_t expected_answer = 0x40f2fd1deb11c6d2;
     uint32_t actual_fpscr, expected_fpscr = 0x4000;
     reset_fpscr();
     asm volatile("fsub %0, %1, %2" : "=f"(c.d) : "f"(123456.78),  
"f"(45678.91011));
     actual_fpscr = get_fpscr();
     if (actual_fpscr == expected_fpscr && c.i == expected_answer) {
         printf("fsub test passed\n");
     } else {
         test_failed("fsub test failed", actual_fpscr,  
expected_fpscr, c.i, expected_answer);
     }
}

/* Test the fsubs instruction */
void test_fsubs()
{
     Converter c;
     double expected_answer = 0x40884e3d70a3d70a;
     uint32_t actual_fpscr, expected_fpscr = 0x4000;
     reset_fpscr();
     asm volatile("fsub %0, %1, %2" : "=f"(c.d) : "f"(1234.56),  
"f"(456.78));
     actual_fpscr = get_fpscr();
     if (actual_fpscr == expected_fpscr && c.i == expected_answer) {
         printf("fsubs test passed\n");
     } else {
         test_failed("fsubs test failed", actual_fpscr,  
expected_fpscr, c.i, expected_answer);
     }
}

/* Test infinity - infinity */
void test_inf_minus_inf()
{
     Converter c;
     uint64_t expected_answer = 0x7ff8000000000000;
     uint32_t actual_fpscr, expected_fpscr = 0xa0811000;
     reset_fpscr();
     asm volatile("fsub %0, %1, %1" : "=f"(c.d) : "f"(INFINITY));
     actual_fpscr = get_fpscr();
     if (actual_fpscr == expected_fpscr && c.i == expected_answer) {
         printf("inf - inf test passed\n");
     } else {
         test_failed("inf - inf test failed", actual_fpscr,  
expected_fpscr, c.i, expected_answer);
     }
}

/* Test division by zero */
void test_division_by_zero()
{
     Converter c;
     uint64_t expected_answer = 0x0;
     uint32_t actual_fpscr, expected_fpscr = 0xc4000010;
     reset_fpscr();
     set_fpscr_bit(ZE);
     asm volatile("fdiv %0, %1, %2" : "=f"(c.d) : "f"(1.0), "f"(0.0));
     actual_fpscr = get_fpscr();
     if (actual_fpscr == expected_fpscr && c.i == expected_answer) {
         printf("division by zero test passed\n");
     } else {
         test_failed("division by zero test failed", actual_fpscr,  
expected_fpscr, c.i, expected_answer);
     }
}

/* Test zero divided by zero */
void test_zero_div_zero()
{
     Converter c;
     uint64_t expected_answer = 0x7ff8000000000000;
     uint32_t actual_fpscr, expected_fpscr = 0xa0211010;
     reset_fpscr();
     set_fpscr_bit(ZE);
     asm volatile("fdiv %0, %1, %1" : "=f"(c.d) : "f"(0.0), "f"(0.0));
     actual_fpscr = get_fpscr();
     if (actual_fpscr == expected_fpscr && c.i == expected_answer) {
         printf("0/0 test passed\n");
     } else {
         test_failed("0/0 test failed", actual_fpscr, expected_fpscr,  
c.i, expected_answer);
     }
}

/* Test infinity divided by infinity */
void test_inf_div_inf()
{
     Converter c;
     uint64_t expected_answer = 0x7ff8000000000000;
     uint32_t actual_fpscr, expected_fpscr = 0xa0411000;
     reset_fpscr();
     asm volatile("fdiv %0, %1, %1" : "=f"(c.d) : "f"(INFINITY));
     actual_fpscr = get_fpscr();
     if (actual_fpscr == expected_fpscr && c.i == expected_answer) {
         printf("inf/inf test passed\n");
     } else {
         test_failed("inf/inf test failed", actual_fpscr,  
expected_fpscr, c.i, expected_answer);
     }
}


/* Test the fdiv instruction */
void test_fdiv()
{
     Converter c;
     uint64_t expected_answer = 0x40059f38ee13b48b;
     uint32_t actual_fpscr, expected_fpscr = 0x82064000;
     reset_fpscr();
     asm volatile("fdiv %0, %1, %2" : "=f"(c.d) : "f"(1234.56),  
"f"(456.78));
     actual_fpscr = get_fpscr();
     if (actual_fpscr == expected_fpscr && c.i == expected_answer) {
         printf("fdiv test passed\n");
     } else {
         test_failed("fdiv test failed", actual_fpscr,  
expected_fpscr, c.i, expected_answer);
     }
}

/* Test the fdivs instruction */
void test_fdivs()
{
     Converter c;
     uint64_t expected_answer = 0x40059f38e0000000;
     uint32_t actual_fpscr, expected_fpscr = 0x82024000;
     reset_fpscr();
     asm volatile("fdivs %0, %1, %2" : "=f"(c.d) : "f"(1234.56),  
"f"(456.78));
     actual_fpscr = get_fpscr();
     if (actual_fpscr == expected_fpscr && c.i == expected_answer) {
         printf("fdivs test passed\n");
     } else {
         test_failed("fdivs test failed", actual_fpscr,  
expected_fpscr, c.i, expected_answer);
     }
}

/* Test the fmul instruction */
void test_fmul()
{
     Converter c;
     uint64_t expected_answer = 0x40365c28f5c28f5c;
     uint32_t actual_fpscr, expected_fpscr = 0x82024000;
     reset_fpscr();
     asm volatile("fmul %0, %1, %2" : "=f"(c.d) : "f"(5.2), "f"(4.3));
     actual_fpscr = get_fpscr();
     if (actual_fpscr == expected_fpscr && c.i == expected_answer) {
         printf("fmul test passed\n");
     } else {
         test_failed("fmul test failed", actual_fpscr,  
expected_fpscr, c.i, expected_answer);
     }
}

/* Test the fmuls instruction */
void test_fmuls()
{
     Converter c;
     uint64_t expected_answer = 0x412135a4a0000000;
     uint32_t actual_fpscr, expected_fpscr = 0x82024000;
     reset_fpscr();
     asm volatile("fmuls %0, %1, %2" : "=f"(c.d) : "f"(1234.56),  
"f"(456.78));
     actual_fpscr = get_fpscr();
     if (actual_fpscr == expected_fpscr && c.i == expected_answer) {
         printf("fmuls test passed\n");
     } else {
         test_failed("fmuls test failed", actual_fpscr,  
expected_fpscr, c.i, expected_answer);
     }
}

/* Test the fmul instruction */
void test_inf_times_zero()
{
     Converter c;
     uint64_t expected_answer = 0x7ff8000000000000;
     uint32_t actual_fpscr, expected_fpscr = 0xa0111000;
     reset_fpscr();
     asm volatile("fmul %0, %1, %2" : "=f"(c.d) : "f"(INFINITY),  
"f"(0.0));
     actual_fpscr = get_fpscr();
     if (actual_fpscr == expected_fpscr && c.i == expected_answer) {
         printf("inf * 0 test passed\n");
     } else {
         test_failed("inf * 0 test failed", actual_fpscr,  
expected_fpscr, c.i, expected_answer);
     }
}

/* Test the fmadd instruction */
void test_fmadd()
{
     Converter c;
     uint64_t expected_answer = 0x4123fcaadfa43fe5;
     uint32_t actual_fpscr, expected_fpscr = 0x82024000;
     reset_fpscr();
     asm volatile("fmadd %0, %1, %2, %3" : "=f"(c.d) : "f"(1234.56),  
"f"(456.78), "f"(91011.12));
     actual_fpscr = get_fpscr();
     if (actual_fpscr == expected_fpscr && c.i == expected_answer) {
         printf("fmadd test passed\n");
     } else {
         test_failed("fmadd test failed", actual_fpscr,  
expected_fpscr, c.i, expected_answer);
     }
}

/* Test the fmadds instruction */
void test_fmadds()
{
     Converter c;
     uint64_t expected_answer = 0x4123fcaae0000000;
     uint32_t actual_fpscr, expected_fpscr = 0x82064000;
     reset_fpscr();
     asm volatile("fmadds %0, %1, %2, %3" : "=f"(c.d) : "f"(1234.56),  
"f"(456.78), "f"(91011.12));
     actual_fpscr = get_fpscr();
     if (actual_fpscr == expected_fpscr && c.i == expected_answer) {
         printf("fmadds test passed\n");
     } else {
         test_failed("fmadds test failed", actual_fpscr,  
expected_fpscr, c.i, expected_answer);
     }
}

/* Test the fsqrt instruction - This instruction doesn't work on the  
PowerPC 750 (G3).
    It does work on the PowerPC 970 (G5).  */
/*void test_fsqrt()
{
     double answer;
     reset_fpscr();
     asm volatile("fsqrt %0, %1" : "=f"(answer) : "f"(-1.0));
     if (get_fpscr() == 0xa0011200) {
         printf("fsqrt test passed\n");
     } else {
         test_failed("fsqrt test failed");
     }
}*/

/* Test an overflow condition */
void test_overflow()
{
     // multiplying two really big numbers equals overflow
     Converter c;
     double really_big_input;
     uint64_t expected_answer = 0x7ff0000000000000;
     uint32_t actual_fpscr, expected_fpscr = 0x92025000;
     reset_fpscr();
     really_big_input = 1.7 * pow(10, 308);
     asm volatile("fmul %0, %1, %1" : "=f"(c.d) :  
"f"(really_big_input));
     actual_fpscr = get_fpscr();
     if (actual_fpscr == expected_fpscr && c.i == expected_answer) {
         printf("overflow test passed\n");
     } else {
         test_failed("overflow test failed", actual_fpscr,  
expected_fpscr, c.i, expected_answer);
     }
}

/* Test an underflow condition */
void test_underflow()
{
     Converter c;
     uint64_t expected_answer = 0x199999999999a;
     uint32_t actual_fpscr, expected_fpscr = 0x8a074000;
     reset_fpscr();
     asm volatile("fmadd %0, %1, %2, %3" : "=f"(c.d) : "f"(DBL_MIN),  
"f"(0.1), "f"(0.0));
     actual_fpscr = get_fpscr();
     if (actual_fpscr == expected_fpscr && c.i == expected_answer) {
         printf("underflow test passed\n");
     } else {
         test_failed("underflow test failed", actual_fpscr,  
expected_fpscr, c.i, expected_answer);
     }
}

/* Test the fctiw instruction */
void test_fctiw()
{
     Converter c;
     uint64_t expected_answer;
     uint32_t actual_fpscr, expected_fpscr;
     double frB;

     /* above maximum value test */
     expected_fpscr = 0xa0000100;
     expected_answer = 0x7fffffff;
     frB = pow(2, 32); // greater than 2^31 - 1
     reset_fpscr();
     asm volatile("fctiw %0, %1" : "=f"(c.d) : "f"(frB));
     actual_fpscr = get_fpscr();
     if (actual_fpscr == expected_fpscr && (c.i & 0xffffffff) ==  
expected_answer) {
         printf("fctiw above maximum value test passed\n");
     } else {
         test_failed("fctiw above maximum value test failed",  
actual_fpscr, expected_fpscr, c.i, expected_answer);
     }

     /* below minimum value test*/
     expected_fpscr = 0xa0000100;
     expected_answer = 0x80000000;
     frB = -frB;  // less than -2^31
     reset_fpscr();
     asm volatile("fctiw %0, %1" : "=f"(c.d) : "f"(frB));
     actual_fpscr = get_fpscr();
     if (actual_fpscr == expected_fpscr && (c.i & 0xffffffff) ==  
expected_answer) {
         printf("fctiw below minimum value test passed\n");
     } else {
         test_failed("fctiw below minimum value test failed",  
actual_fpscr, expected_fpscr, c.i, expected_answer);
     }

     /* float to integer test */
     expected_fpscr = 0x82060000;
     expected_answer = 0xfff800000000000d;
     reset_fpscr();
     asm volatile("fctiw %0, %1" : "=f"(c.d) : "f"(12.7));
     actual_fpscr = get_fpscr();
     if (actual_fpscr == expected_fpscr && c.i == expected_answer) {
         printf("fctiw integer conversion test passed\n");
     } else {
         test_failed("fctiw integer conversion test failed",  
actual_fpscr, expected_fpscr, c.i, expected_answer);
     }
}

/* Test the fctiwz instruction */
void test_fctiwz()
{
     Converter c;
     uint64_t expected_answer;
     uint32_t actual_fpscr, expected_fpscr;
     double frB;

     /* above maximum value test */
     expected_fpscr = 0xa0000100;
     expected_answer = 0x7fffffff;
     frB = pow(2, 32); // greater than 2^31 - 1
     reset_fpscr();
     asm volatile("fctiwz %0, %1" : "=f"(c.d) : "f"(frB));
     actual_fpscr = get_fpscr();
     if (actual_fpscr == expected_fpscr && (c.i & 0xffffffff) ==  
expected_answer) {
         printf("fctiwz above maximum value test passed\n");
     } else {
         test_failed("fctiwz above maximum value test failed",  
actual_fpscr, expected_fpscr, c.i, expected_answer);
     }

     /* below minimum value test*/
     expected_fpscr = 0xa0000100;
     expected_answer = 0x80000000;
     frB = -frB;  // less than -2^31
     reset_fpscr();
     asm volatile("fctiwz %0, %1" : "=f"(c.d) : "f"(frB));
     actual_fpscr = get_fpscr();
     if (actual_fpscr == expected_fpscr && (c.i & 0xffffffff) ==  
expected_answer) {
         printf("fctiwz below minimum value test passed\n");
     } else {
         test_failed("fctiwz below minimum value test failed",  
actual_fpscr, expected_fpscr, c.i, expected_answer);
     }

     /* float to integer test */
     expected_fpscr = 0x82060000;
     expected_answer = 0xfff800000000001c;
     reset_fpscr();
     asm volatile("fctiw %0, %1" : "=f"(c.d) : "f"(27.98));
     actual_fpscr = get_fpscr();
     if (actual_fpscr == expected_fpscr && c.i == expected_answer) {
         printf("fctiwz integer conversion test passed\n");
     } else {
         test_failed("fctiwz integer conversion test failed",  
actual_fpscr, expected_fpscr, c.i, expected_answer);
     }
}

/* Test the frsp instruction */
void test_frsp()
{
     Converter c;
     uint64_t expected_answer = 0x4271f71fc0000000;
     uint32_t actual_fpscr, expected_fpscr = 0x82064000;
     reset_fpscr();
     asm volatile("frsp %0, %1" : "=f"(c.d) :  
"f"(1234567891012.131415));
     actual_fpscr = get_fpscr();
     if (actual_fpscr == expected_fpscr && c.i == expected_answer) {
         printf("frsp test passed\n");
     } else {
         test_failed("frsp test failed", actual_fpscr,  
expected_fpscr, c.i, expected_answer);
     }
}

/* Test the fnmsub instruction */
void test_fnmsub()
{
     Converter c;
     uint64_t expected_answer = 0xc11cdd3cc985f06e;
     uint32_t actual_fpscr, expected_fpscr = 0x82028000;
     reset_fpscr();
     asm volatile("fnmsub %0, %1, %2, %3" : "=f"(c.d) : "f"(1234.56),  
"f"(456.78), "f"(91011.12));
     actual_fpscr = get_fpscr();
     if (actual_fpscr == expected_fpscr && c.i == expected_answer) {
         printf("fnmsub test passed\n");
     } else {
         test_failed("fnmsub test failed", actual_fpscr,  
expected_fpscr, c.i, expected_answer);
     }
}

/* Report the results of all the tests */
void report_results()
{
     if (failed_tests == 1) {
         printf("\n=== Warning: %d test failed ===\n", failed_tests);
     } else if (failed_tests > 1) {
         printf("\n=== Warning: %d tests failed ===\n", failed_tests);
     } else {
         printf("\n=== All tests passed ===\n");
     }
}

int main (int argc, const char * argv[]) {

     test_fadd();
     test_fadds();
     test_fsub();
     test_fsubs();
     test_fmul();
     test_fmuls();
     test_fdiv();
     test_fdivs();
     test_fmadd();
     test_fmadds();
     //test_fsqrt();
     test_inf_minus_inf();
     test_division_by_zero();
     test_zero_div_zero();
     test_inf_div_inf();
     test_inf_times_zero();
     test_overflow();
     test_underflow();
     test_fctiw();
     test_fctiwz();
     test_frsp();
     test_fnmsub();

     report_results();

     return 0;
}


Here is the full test results after running this program in qemu- 
system-ppc with a Mac OS 10.4 guest:




fadd test failed
expected answer: 0x3ff3333333333334
   actual answer: 0x8200400000000024
expected fpscr: 0x82064000
   actual fpscr: 0x82004000

actual FPSCR bits set:
bit 17: FPRF - Floating-point greater than or positive
bit 6: XX - Floating-point inexact exception
bit 0: FX - Floating-point exception summary

expected FPSCR bits set:
bit 17: FPRF - Floating-point greater than or positive
bit 14: FI - Floating-point fraction inexact
bit 13: FR - Floating-point fraction rounded
bit 6: XX - Floating-point inexact exception
bit 0: FX - Floating-point exception summary

fadds test failed
expected answer: 0x407024d500000000
   actual answer: 0x8200400000000024
expected fpscr: 0x82064000
   actual fpscr: 0x82004000

actual FPSCR bits set:
bit 17: FPRF - Floating-point greater than or positive
bit 6: XX - Floating-point inexact exception
bit 0: FX - Floating-point exception summary

expected FPSCR bits set:
bit 17: FPRF - Floating-point greater than or positive
bit 14: FI - Floating-point fraction inexact
bit 13: FR - Floating-point fraction rounded
bit 6: XX - Floating-point inexact exception
bit 0: FX - Floating-point exception summary

fsub test passed
fsubs test passed
fmul test failed
expected answer: 0x40365c28f5c28f5c
   actual answer: 0x8200400000000024
expected fpscr: 0x82024000
   actual fpscr: 0x82004000

actual FPSCR bits set:
bit 17: FPRF - Floating-point greater than or positive
bit 6: XX - Floating-point inexact exception
bit 0: FX - Floating-point exception summary

expected FPSCR bits set:
bit 17: FPRF - Floating-point greater than or positive
bit 14: FI - Floating-point fraction inexact
bit 6: XX - Floating-point inexact exception
bit 0: FX - Floating-point exception summary

fmuls test failed
expected answer: 0x412135a4a0000000
   actual answer: 0x8200400000000024
expected fpscr: 0x82024000
   actual fpscr: 0x82004000

actual FPSCR bits set:
bit 17: FPRF - Floating-point greater than or positive
bit 6: XX - Floating-point inexact exception
bit 0: FX - Floating-point exception summary

expected FPSCR bits set:
bit 17: FPRF - Floating-point greater than or positive
bit 14: FI - Floating-point fraction inexact
bit 6: XX - Floating-point inexact exception
bit 0: FX - Floating-point exception summary

fdiv test failed
expected answer: 0x40059f38ee13b48b
   actual answer: 0x8200400000000024
expected fpscr: 0x82064000
   actual fpscr: 0x82004000

actual FPSCR bits set:
bit 17: FPRF - Floating-point greater than or positive
bit 6: XX - Floating-point inexact exception
bit 0: FX - Floating-point exception summary

expected FPSCR bits set:
bit 17: FPRF - Floating-point greater than or positive
bit 14: FI - Floating-point fraction inexact
bit 13: FR - Floating-point fraction rounded
bit 6: XX - Floating-point inexact exception
bit 0: FX - Floating-point exception summary

fdivs test failed
expected answer: 0x40059f38e0000000
   actual answer: 0x8200400000000024
expected fpscr: 0x82024000
   actual fpscr: 0x82004000

actual FPSCR bits set:
bit 17: FPRF - Floating-point greater than or positive
bit 6: XX - Floating-point inexact exception
bit 0: FX - Floating-point exception summary

expected FPSCR bits set:
bit 17: FPRF - Floating-point greater than or positive
bit 14: FI - Floating-point fraction inexact
bit 6: XX - Floating-point inexact exception
bit 0: FX - Floating-point exception summary

fmadd test failed
expected answer: 0x4123fcaadfa43fe5
   actual answer: 0x8200400000000024
expected fpscr: 0x82024000
   actual fpscr: 0x82004000

actual FPSCR bits set:
bit 17: FPRF - Floating-point greater than or positive
bit 6: XX - Floating-point inexact exception
bit 0: FX - Floating-point exception summary

expected FPSCR bits set:
bit 17: FPRF - Floating-point greater than or positive
bit 14: FI - Floating-point fraction inexact
bit 6: XX - Floating-point inexact exception
bit 0: FX - Floating-point exception summary

fmadds test failed
expected answer: 0x4123fcaae0000000
   actual answer: 0x8200400000000024
expected fpscr: 0x82064000
   actual fpscr: 0x82004000

actual FPSCR bits set:
bit 17: FPRF - Floating-point greater than or positive
bit 6: XX - Floating-point inexact exception
bit 0: FX - Floating-point exception summary

expected FPSCR bits set:
bit 17: FPRF - Floating-point greater than or positive
bit 14: FI - Floating-point fraction inexact
bit 13: FR - Floating-point fraction rounded
bit 6: XX - Floating-point inexact exception
bit 0: FX - Floating-point exception summary

inf - inf test passed
Warning: fpscr not equal to zero: 0x20000000
division by zero test failed
expected answer: 0x0
   actual answer: 0xc400501000000015
expected fpscr: 0xc4000010
   actual fpscr: 0xc4005010

actual FPSCR bits set:
bit 27: ZE - IEEE floating-point zero divide exception enable
bit 19: FPRF - Floating-point unordered or NaN
bit 17: FPRF - Floating-point greater than or positive
bit 5: ZX - Floating-point zero divide exception
bit 1: FEX - Floating-point enabled exception summary
bit 0: FX - Floating-point exception summary

expected FPSCR bits set:
bit 27: ZE - IEEE floating-point zero divide exception enable
bit 5: ZX - Floating-point zero divide exception
bit 1: FEX - Floating-point enabled exception summary
bit 0: FX - Floating-point exception summary

Warning: fpscr not equal to zero: 0x40000000
0/0 test passed
Warning: fpscr not equal to zero: 0x20000000
inf/inf test passed
Warning: fpscr not equal to zero: 0x20000000
inf * 0 test passed
Warning: fpscr not equal to zero: 0x20000000
overflow test passed
underflow test failed
expected answer: 0x199999999999a
   actual answer: 0x8801400000000021
expected fpscr: 0x8a074000
   actual fpscr: 0x88014000

actual FPSCR bits set:
bit 17: FPRF - Floating-point greater than or positive
bit 15: FPRF - Floating-point result class descriptor
bit 4: UX - Floating-point underflow exception
bit 0: FX - Floating-point exception summary

expected FPSCR bits set:
bit 17: FPRF - Floating-point greater than or positive
bit 15: FPRF - Floating-point result class descriptor
bit 14: FI - Floating-point fraction inexact
bit 13: FR - Floating-point fraction rounded
bit 6: XX - Floating-point inexact exception
bit 4: UX - Floating-point underflow exception
bit 0: FX - Floating-point exception summary

fctiw above maximum value test failed
expected answer: 0x7fffffff
   actual answer: 0xa00111000000001c
expected fpscr: 0xa0000100
   actual fpscr: 0xa0011100

actual FPSCR bits set:
bit 23: VXCVI - Floating-point invalid operation exception for  
invalid integer convert
bit 19: FPRF - Floating-point unordered or NaN
bit 15: FPRF - Floating-point result class descriptor
bit 2: VX - Floating-point invalid operation exception summary
bit 0: FX - Floating-point exception summary

expected FPSCR bits set:
bit 23: VXCVI - Floating-point invalid operation exception for  
invalid integer convert
bit 2: VX - Floating-point invalid operation exception summary
bit 0: FX - Floating-point exception summary

Warning: fpscr not equal to zero: 0x20000000
fctiw below minimum value test failed
expected answer: 0x80000000
   actual answer: 0xa00111000000001c
expected fpscr: 0xa0000100
   actual fpscr: 0xa0011100

actual FPSCR bits set:
bit 23: VXCVI - Floating-point invalid operation exception for  
invalid integer convert
bit 19: FPRF - Floating-point unordered or NaN
bit 15: FPRF - Floating-point result class descriptor
bit 2: VX - Floating-point invalid operation exception summary
bit 0: FX - Floating-point exception summary

expected FPSCR bits set:
bit 23: VXCVI - Floating-point invalid operation exception for  
invalid integer convert
bit 2: VX - Floating-point invalid operation exception summary
bit 0: FX - Floating-point exception summary

Warning: fpscr not equal to zero: 0x20000000
fctiw integer conversion test failed
expected answer: 0xfff800000000000d
   actual answer: 0x8200000000000024
expected fpscr: 0x82060000
   actual fpscr: 0x82000000

actual FPSCR bits set:
bit 6: XX - Floating-point inexact exception
bit 0: FX - Floating-point exception summary

expected FPSCR bits set:
bit 14: FI - Floating-point fraction inexact
bit 13: FR - Floating-point fraction rounded
bit 6: XX - Floating-point inexact exception
bit 0: FX - Floating-point exception summary

fctiwz above maximum value test failed
expected answer: 0x7fffffff
   actual answer: 0xa00111000000001c
expected fpscr: 0xa0000100
   actual fpscr: 0xa0011100

actual FPSCR bits set:
bit 23: VXCVI - Floating-point invalid operation exception for  
invalid integer convert
bit 19: FPRF - Floating-point unordered or NaN
bit 15: FPRF - Floating-point result class descriptor
bit 2: VX - Floating-point invalid operation exception summary
bit 0: FX - Floating-point exception summary

expected FPSCR bits set:
bit 23: VXCVI - Floating-point invalid operation exception for  
invalid integer convert
bit 2: VX - Floating-point invalid operation exception summary
bit 0: FX - Floating-point exception summary

Warning: fpscr not equal to zero: 0x20000000
fctiwz below minimum value test failed
expected answer: 0x80000000
   actual answer: 0xa00111000000001c
expected fpscr: 0xa0000100
   actual fpscr: 0xa0011100

actual FPSCR bits set:
bit 23: VXCVI - Floating-point invalid operation exception for  
invalid integer convert
bit 19: FPRF - Floating-point unordered or NaN
bit 15: FPRF - Floating-point result class descriptor
bit 2: VX - Floating-point invalid operation exception summary
bit 0: FX - Floating-point exception summary

expected FPSCR bits set:
bit 23: VXCVI - Floating-point invalid operation exception for  
invalid integer convert
bit 2: VX - Floating-point invalid operation exception summary
bit 0: FX - Floating-point exception summary

Warning: fpscr not equal to zero: 0x20000000
fctiwz integer conversion test failed
expected answer: 0xfff800000000001c
   actual answer: 0x8200000000000024
expected fpscr: 0x82060000
   actual fpscr: 0x82000000

actual FPSCR bits set:
bit 6: XX - Floating-point inexact exception
bit 0: FX - Floating-point exception summary

expected FPSCR bits set:
bit 14: FI - Floating-point fraction inexact
bit 13: FR - Floating-point fraction rounded
bit 6: XX - Floating-point inexact exception
bit 0: FX - Floating-point exception summary

frsp test failed
expected answer: 0x4271f71fc0000000
   actual answer: 0x8200400000000024
expected fpscr: 0x82064000
   actual fpscr: 0x82004000

actual FPSCR bits set:
bit 17: FPRF - Floating-point greater than or positive
bit 6: XX - Floating-point inexact exception
bit 0: FX - Floating-point exception summary

expected FPSCR bits set:
bit 17: FPRF - Floating-point greater than or positive
bit 14: FI - Floating-point fraction inexact
bit 13: FR - Floating-point fraction rounded
bit 6: XX - Floating-point inexact exception
bit 0: FX - Floating-point exception summary

fnmsub test failed
expected answer: 0xc11cdd3cc985f06e
   actual answer: 0x8200800000000024
expected fpscr: 0x82028000
   actual fpscr: 0x82008000

actual FPSCR bits set:
bit 16: FPRF - Floating-point less than or negative
bit 6: XX - Floating-point inexact exception
bit 0: FX - Floating-point exception summary

expected FPSCR bits set:
bit 16: FPRF - Floating-point less than or negative
bit 14: FI - Floating-point fraction inexact
bit 6: XX - Floating-point inexact exception
bit 0: FX - Floating-point exception summary


=== Warning: 18 tests failed ===


It looks like the floating point instructions need a little work. 

Re: [Qemu-devel] Floating point unit bugs

[Aurelien Jarno]

On 2017-05-07 17:48, G 3 wrote:
> I made a diagnostic program for the floating point unit. It will test
> various PowerPC floating point instructions for compatibility with the
> PowerPC G3 processor. It was tested on a PowerPC G3 and G5 system. The
> results of the program in qemu-system-ppc were pretty bad. About every
> instruction tested is not implemented correctly.

I don't say that qemu-system-ppc is bug free, but this looks suspicious
that about every instruction is buggy. Have you tried to run your
program on a real G3 or G5 system?

[ snip ]

> 
> Here is the full test results after running this program in qemu-system-ppc
> with a Mac OS 10.4 guest:
> 
> 
> 
> 
> fadd test failed
> expected answer: 0x3ff3333333333334
>   actual answer: 0x8200400000000024
> expected fpscr: 0x82064000
>   actual fpscr: 0x82004000

This looks highly suspicious that the actual answer match the expected
answer.

> actual FPSCR bits set:
> bit 17: FPRF - Floating-point greater than or positive
> bit 6: XX - Floating-point inexact exception
> bit 0: FX - Floating-point exception summary
> 
> expected FPSCR bits set:
> bit 17: FPRF - Floating-point greater than or positive
> bit 14: FI - Floating-point fraction inexact
> bit 13: FR - Floating-point fraction rounded
> bit 6: XX - Floating-point inexact exception
> bit 0: FX - Floating-point exception summary
> 
> fadds test failed
> expected answer: 0x407024d500000000
>   actual answer: 0x8200400000000024
> expected fpscr: 0x82064000
>   actual fpscr: 0x82004000

Ditto.

> actual FPSCR bits set:
> bit 17: FPRF - Floating-point greater than or positive
> bit 6: XX - Floating-point inexact exception
> bit 0: FX - Floating-point exception summary
> 
> expected FPSCR bits set:
> bit 17: FPRF - Floating-point greater than or positive
> bit 14: FI - Floating-point fraction inexact
> bit 13: FR - Floating-point fraction rounded
> bit 6: XX - Floating-point inexact exception
> bit 0: FX - Floating-point exception summary
> 
> fsub test passed
> fsubs test passed
> fmul test failed
> expected answer: 0x40365c28f5c28f5c
>   actual answer: 0x8200400000000024
> expected fpscr: 0x82024000
>   actual fpscr: 0x82004000

Ditto.

> actual FPSCR bits set:
> bit 17: FPRF - Floating-point greater than or positive
> bit 6: XX - Floating-point inexact exception
> bit 0: FX - Floating-point exception summary
> 
> expected FPSCR bits set:
> bit 17: FPRF - Floating-point greater than or positive
> bit 14: FI - Floating-point fraction inexact
> bit 6: XX - Floating-point inexact exception
> bit 0: FX - Floating-point exception summary
> 
> fmuls test failed
> expected answer: 0x412135a4a0000000
>   actual answer: 0x8200400000000024
> expected fpscr: 0x82024000
>   actual fpscr: 0x82004000
> 
> actual FPSCR bits set:
> bit 17: FPRF - Floating-point greater than or positive
> bit 6: XX - Floating-point inexact exception
> bit 0: FX - Floating-point exception summary
> 
> expected FPSCR bits set:
> bit 17: FPRF - Floating-point greater than or positive
> bit 14: FI - Floating-point fraction inexact
> bit 6: XX - Floating-point inexact exception
> bit 0: FX - Floating-point exception summary
> 
> fdiv test failed
> expected answer: 0x40059f38ee13b48b
>   actual answer: 0x8200400000000024
> expected fpscr: 0x82064000
>   actual fpscr: 0x82004000

Ditto.

And so on...

-- 
Aurelien Jarno                          GPG: 4096R/1DDD8C9B
aurelien@aurel32.net                 http://www.aurel32.net

Re: [Qemu-devel] Floating point unit bugs

[G 3]

On May 8, 2017, at 5:54 PM, Aurelien Jarno wrote:

> On 2017-05-07 17:48, G 3 wrote:
>> I made a diagnostic program for the floating point unit. It will test
>> various PowerPC floating point instructions for compatibility with  
>> the
>> PowerPC G3 processor. It was tested on a PowerPC G3 and G5 system.  
>> The
>> results of the program in qemu-system-ppc were pretty bad. About  
>> every
>> instruction tested is not implemented correctly.
>
> I don't say that qemu-system-ppc is bug free, but this looks  
> suspicious
> that about every instruction is buggy.

I really hope you don't think I'm blaming anyone. I'm only reporting  
the results of the test.

> Have you tried to run your
> program on a real G3 or G5 system?

Yes. I made sure it ran on a real G3 and G5 system without problem  
before testing it on QEMU. I suspect the Motorola designed G4  
processor will not be compatible. I don't have a working G4 system to  
verify this unfortunately.

>
> [ snip ]
>
>>
>> Here is the full test results after running this program in qemu- 
>> system-ppc
>> with a Mac OS 10.4 guest:
>>
>>
>>
>>
>> fadd test failed
>> expected answer: 0x3ff3333333333334
>>   actual answer: 0x8200400000000024
>> expected fpscr: 0x82064000
>>   actual fpscr: 0x82004000
>
> This looks highly suspicious that the actual answer match the expected
> answer.

You can use this web page to find the decimal value: http:// 
www6.uniovi.es/~antonio/uned/ieee754/IEEE-754hex64.html

0x3ff3333333333334 = 1.2000000000000002
0x8200400000000024 = -4.8529708162167760e-299

The expected answer and actual answer are very far from each other.

Re: [Qemu-devel] Floating point unit bugs

[Aurelien Jarno]

On 2017-05-08 18:09, G 3 wrote:
> 
> On May 8, 2017, at 5:54 PM, Aurelien Jarno wrote:
> 
> > On 2017-05-07 17:48, G 3 wrote:
> > > I made a diagnostic program for the floating point unit. It will test
> > > various PowerPC floating point instructions for compatibility with
> > > the
> > > PowerPC G3 processor. It was tested on a PowerPC G3 and G5 system.
> > > The
> > > results of the program in qemu-system-ppc were pretty bad. About
> > > every
> > > instruction tested is not implemented correctly.
> > 
> > I don't say that qemu-system-ppc is bug free, but this looks suspicious
> > that about every instruction is buggy.
> 
> I really hope you don't think I'm blaming anyone. I'm only reporting the
> results of the test.
> 
> > Have you tried to run your
> > program on a real G3 or G5 system?
> 
> Yes. I made sure it ran on a real G3 and G5 system without problem before
> testing it on QEMU. I suspect the Motorola designed G4 processor will not be
> compatible. I don't have a working G4 system to verify this unfortunately.
> 
> > 
> > [ snip ]
> > 
> > > 
> > > Here is the full test results after running this program in qemu-system-ppc
> > > with a Mac OS 10.4 guest:
> > > 
> > > 
> > > 
> > > 
> > > fadd test failed
> > > expected answer: 0x3ff3333333333334
> > >   actual answer: 0x8200400000000024
> > > expected fpscr: 0x82064000
> > >   actual fpscr: 0x82004000
> > 
> > This looks highly suspicious that the actual answer match the expected
> > answer.
> 
> You can use this web page to find the decimal value: http://www6.uniovi.es/~antonio/uned/ieee754/IEEE-754hex64.html
> 
> 0x3ff3333333333334 = 1.2000000000000002
> 0x8200400000000024 = -4.8529708162167760e-299
> 
> The expected answer and actual answer are very far from each other.

Yes, I made a typo in my comment. I wanted to say that I found very
suspicious that the actual answer match the actual fpscr. See my other
mail for the reason.

-- 
Aurelien Jarno                          GPG: 4096R/1DDD8C9B
aurelien@aurel32.net                 http://www.aurel32.net

Re: [Qemu-devel] Floating point unit bugs

[Aurelien Jarno]

On 2017-05-07 17:48, G 3 wrote:
> I made a diagnostic program for the floating point unit. It will test
> various PowerPC floating point instructions for compatibility with the
> PowerPC G3 processor. It was tested on a PowerPC G3 and G5 system. The
> results of the program in qemu-system-ppc were pretty bad. About every
> instruction tested is not implemented correctly.
> 
> Here is the download link to the program: http://www.mediafire.com/file/6j9tqubvk73lkw1/floating_point_test_program.zip

Some comments on the code.
> 
>     /* Check if everything is alright */
>     uint32_t fpscr;
>     asm volatile("mffs f0");
>     asm volatile("stfd f0, 40(r1)");
>     asm volatile("lwz %0, 44(r1)" : "=r"(fpscr));
>     if (fpscr != 0) {
>         printf("Warning: fpscr not equal to zero: 0x%x\n", fpscr);
>     }

This is overly complicated and just doesn't compile with recent GCC
versions. What about something like:

    Converter c;
    asm volatile("mffs %0" : "=f"(c.d));
    fpscr = (uint32_t)c.i;


> /*
>  * The action to take if a test fails
>  * Input one: message string
>  * Input two: actual fpscr value
>  * Input three: expected fpscr value
>  * Input four: actual answer
>  * Input five: expected answer
>  */
>  void test_failed(const char *message, uint32_t actual_fpscr, uint32_t
> expected_fpscr,
>                   uint64_t actual_answer, uint64_t expected_answer)
>  {
>     printf("%s\n", message);
>     printf("expected answer: 0x%" PRIx64 "\n", expected_answer);
>     printf("  actual answer: 0x%" PRIx64 "\n", actual_fpscr);

This is wrong. It should be actual_answer instead of actual_fpscr. That
is why all the instructions seems totally wrongly implemented. Note that
compiling with -Wall would give you a warning:

| main.c: In function ‘test_failed’:
| main.c:146:5: warning: format ‘%llx’ expects argument of type ‘long long unsigned int’, but argument 2 has type ‘uint32_t’ [-Wformat=]
|      printf("  actual answer: 0x%" PRIx64 "\n", actual_fpscr);
|      ^

So I think the cone needs to be improved a bit before we can conclude
anything.

Aurelien

-- 
Aurelien Jarno                          GPG: 4096R/1DDD8C9B
aurelien@aurel32.net                 http://www.aurel32.net

Re: [Qemu-devel] Floating point unit bugs

[G 3]

On May 8, 2017, at 6:13 PM, Aurelien Jarno wrote:

> On 2017-05-07 17:48, G 3 wrote:
>> I made a diagnostic program for the floating point unit. It will test
>> various PowerPC floating point instructions for compatibility with  
>> the
>> PowerPC G3 processor. It was tested on a PowerPC G3 and G5 system.  
>> The
>> results of the program in qemu-system-ppc were pretty bad. About  
>> every
>> instruction tested is not implemented correctly.
>>
>> Here is the download link to the program: http://www.mediafire.com/ 
>> file/6j9tqubvk73lkw1/floating_point_test_program.zip
>
> Some comments on the code.
>>
>>     /* Check if everything is alright */
>>     uint32_t fpscr;
>>     asm volatile("mffs f0");
>>     asm volatile("stfd f0, 40(r1)");
>>     asm volatile("lwz %0, 44(r1)" : "=r"(fpscr));
>>     if (fpscr != 0) {
>>         printf("Warning: fpscr not equal to zero: 0x%x\n", fpscr);
>>     }
>
> This is overly complicated and just doesn't compile with recent GCC
> versions.

Which version of GCC had the problem? GCC 5.2 and GCC 3.3 seems to  
work fine. GCC 4.0 did not work. Could you send me the error message?

> What about something like:
>
>     Converter c;
>     asm volatile("mffs %0" : "=f"(c.d));
>     fpscr = (uint32_t)c.i;

This way does work also.

>
>
>> /*
>>  * The action to take if a test fails
>>  * Input one: message string
>>  * Input two: actual fpscr value
>>  * Input three: expected fpscr value
>>  * Input four: actual answer
>>  * Input five: expected answer
>>  */
>>  void test_failed(const char *message, uint32_t actual_fpscr,  
>> uint32_t
>> expected_fpscr,
>>                   uint64_t actual_answer, uint64_t expected_answer)
>>  {
>>     printf("%s\n", message);
>>     printf("expected answer: 0x%" PRIx64 "\n", expected_answer);
>>     printf("  actual answer: 0x%" PRIx64 "\n", actual_fpscr);
>
> This is wrong. It should be actual_answer instead of actual_fpscr.  
> That
> is why all the instructions seems totally wrongly implemented.

Thanks for catching this error. Actually this would only effect the  
"actual answer:" output field. The comparison between expected_answer  
and actual_answer in each individual test is still valid.

> Note that
> compiling with -Wall would give you a warning:
>
> | main.c: In function ‘test_failed’:
> | main.c:146:5: warning: format ‘%llx’ expects argument of type  
> ‘long long unsigned int’, but argument 2 has type ‘uint32_t’ [- 
> Wformat=]
> |      printf("  actual answer: 0x%" PRIx64 "\n", actual_fpscr);
> |      ^
>

Replacing actual_fpscr with actual_answer should solve this problem.

Re: [Qemu-devel] Floating point unit bugs

[Aurelien Jarno]

On 2017-05-08 18:36, G 3 wrote:
> 
> On May 8, 2017, at 6:13 PM, Aurelien Jarno wrote:
> 
> > On 2017-05-07 17:48, G 3 wrote:
> > > I made a diagnostic program for the floating point unit. It will test
> > > various PowerPC floating point instructions for compatibility with
> > > the
> > > PowerPC G3 processor. It was tested on a PowerPC G3 and G5 system.
> > > The
> > > results of the program in qemu-system-ppc were pretty bad. About
> > > every
> > > instruction tested is not implemented correctly.
> > > 
> > > Here is the download link to the program: http://www.mediafire.com/file/6j9tqubvk73lkw1/floating_point_test_program.zip
> > 
> > Some comments on the code.
> > > 
> > >     /* Check if everything is alright */
> > >     uint32_t fpscr;
> > >     asm volatile("mffs f0");
> > >     asm volatile("stfd f0, 40(r1)");
> > >     asm volatile("lwz %0, 44(r1)" : "=r"(fpscr));
> > >     if (fpscr != 0) {
> > >         printf("Warning: fpscr not equal to zero: 0x%x\n", fpscr);
> > >     }
> > 
> > This is overly complicated and just doesn't compile with recent GCC
> > versions.
> 
> Which version of GCC had the problem? GCC 5.2 and GCC 3.3 seems to work
> fine. GCC 4.0 did not work. Could you send me the error message?

I tried with GCC 4.9. Actually the error message is coming from
binutils:

| main.c:34:5: warning: missing braces around initializer [-Wmissing-braces]
|      "FX", "Floating-point exception summary",
|      ^
| main.c:34:5: warning: (near initialization for 'finfo[0]') [-Wmissing-braces]
| main.c: In function 'print_fpscr_settings':
| main.c:73:26: warning: suggest parentheses around comparison in operand of '&' [-Wparentheses]
|          if ((fpscr >> i) & 0x1 == 1) {
|                           ^
| main.c: In function 'test_failed':
| main.c:146:5: warning: format '%llx' expects argument of type 'long long unsigned int', but argument 2 has type 'uint32_t' [-Wformat=]
|      printf("  actual answer: 0x%" PRIx64 "\n", actual_fpscr);
|      ^
| /tmp/cctHPRx4.s: Assembler messages:
| /tmp/cctHPRx4.s:315: Error: unsupported relocation against f0
| /tmp/cctHPRx4.s:318: Error: unsupported relocation against f0
| /tmp/cctHPRx4.s:318: Error: unsupported relocation against r1
| /tmp/cctHPRx4.s:321: Error: unsupported relocation against r1
| /tmp/cctHPRx4.s:438: Error: unsupported relocation against f0
| /tmp/cctHPRx4.s:441: Error: unsupported relocation against f0
| /tmp/cctHPRx4.s:441: Error: unsupported relocation against r1
| /tmp/cctHPRx4.s:444: Error: unsupported relocation against r1

> > What about something like:
> > 
> >     Converter c;
> >     asm volatile("mffs %0" : "=f"(c.d));
> >     fpscr = (uint32_t)c.i;
> 
> This way does work also.
> 
> > 
> > 
> > > /*
> > >  * The action to take if a test fails
> > >  * Input one: message string
> > >  * Input two: actual fpscr value
> > >  * Input three: expected fpscr value
> > >  * Input four: actual answer
> > >  * Input five: expected answer
> > >  */
> > >  void test_failed(const char *message, uint32_t actual_fpscr,
> > > uint32_t
> > > expected_fpscr,
> > >                   uint64_t actual_answer, uint64_t expected_answer)
> > >  {
> > >     printf("%s\n", message);
> > >     printf("expected answer: 0x%" PRIx64 "\n", expected_answer);
> > >     printf("  actual answer: 0x%" PRIx64 "\n", actual_fpscr);
> > 
> > This is wrong. It should be actual_answer instead of actual_fpscr. That
> > is why all the instructions seems totally wrongly implemented.
> 
> Thanks for catching this error. Actually this would only effect the "actual
> answer:" output field. The comparison between expected_answer and
> actual_answer in each individual test is still valid.

Indeed, but I guess it gives "better" results than what it looks when
looking at your mail where the values are totally wrong.

-- 
Aurelien Jarno                          GPG: 4096R/1DDD8C9B
aurelien@aurel32.net                 http://www.aurel32.net

Re: [Qemu-devel] [Qemu-ppc] Floating point unit bugs

[BALATON Zoltan]

On Tue, 9 May 2017, Aurelien Jarno wrote:
> | main.c: In function 'print_fpscr_settings':
> | main.c:73:26: warning: suggest parentheses around comparison in operand of '&' [-Wparentheses]
> |          if ((fpscr >> i) & 0x1 == 1) {
> |                           ^

Actually the compiler is correct here, this should be:

if ((fpscr >> i & 0x1) == 1) {

or even just

if (fpscr >> i & 1) {

because & is lower priority than == but the result may still be the same 
by chance if 0x1 == 1 is always 1 and ANDing the shifted value with this 
is either 0 or 1 so it may give the correct result but not the way one 
would think looking at the expression.

Regards,
BALATON Zoltan

Re: [Qemu-devel] [Qemu-ppc] Floating point unit bugs

[G 3]

On May 9, 2017, at 5:55 AM, BALATON Zoltan wrote:

> On Tue, 9 May 2017, Aurelien Jarno wrote:
>> | main.c: In function 'print_fpscr_settings':
>> | main.c:73:26: warning: suggest parentheses around comparison in  
>> operand of '&' [-Wparentheses]
>> |          if ((fpscr >> i) & 0x1 == 1) {
>> |                           ^
>
> Actually the compiler is correct here, this should be:
>
> if ((fpscr >> i & 0x1) == 1) {
>
> or even just
>
> if (fpscr >> i & 1) {
>
> because & is lower priority than == but the result may still be the  
> same by chance if 0x1 == 1 is always 1 and ANDing the shifted value  
> with this is either 0 or 1 so it may give the correct result but  
> not the way one would think looking at the expression.

I changed it to this:
if (((fpscr >> i) & 0x1) == 1)

Thank you.

Re: [Qemu-devel] [Qemu-ppc] Floating point unit bugs

[Philippe Mathieu-Daudé]

Hi John,

On 05/09/2017 10:58 AM, G 3 wrote:
>
> On May 9, 2017, at 5:55 AM, BALATON Zoltan wrote:
>
>> On Tue, 9 May 2017, Aurelien Jarno wrote:
>>> | main.c: In function 'print_fpscr_settings':
>>> | main.c:73:26: warning: suggest parentheses around comparison in
>>> operand of '&' [-Wparentheses]
>>> |          if ((fpscr >> i) & 0x1 == 1) {
>>> |                           ^
>>
>> Actually the compiler is correct here, this should be:
>>
>> if ((fpscr >> i & 0x1) == 1) {
>>
>> or even just
>>
>> if (fpscr >> i & 1) {
>>
>> because & is lower priority than == but the result may still be the
>> same by chance if 0x1 == 1 is always 1 and ANDing the shifted value
>> with this is either 0 or 1 so it may give the correct result but not
>> the way one would think looking at the expression.
>
> I changed it to this:
> if (((fpscr >> i) & 0x1) == 1)
>
> Thank you.

do you think you can add your test as a qtest, to run it with check-qtest?

Regards,

Phil.

>

Re: [Qemu-devel] [Qemu-ppc] Floating point unit bugs

[Peter Maydell]

On 21 June 2017 at 17:14, Philippe Mathieu-Daudé <f4bug@amsat.org> wrote:
> do you think you can add your test as a qtest, to run it with check-qtest?

We don't yet have any mechanism for having tests that need to
be compiled for the target architecture, do we?

thanks
-- PMM

Re: [Qemu-devel] [Qemu-ppc] Floating point unit bugs

[G 3]

On Jun 21, 2017, at 12:20 PM, Peter Maydell wrote:

> On 21 June 2017 at 17:14, Philippe Mathieu-Daudé <f4bug@amsat.org>  
> wrote:
>> do you think you can add your test as a qtest, to run it with  
>> check-qtest?
>
> We don't yet have any mechanism for having tests that need to
> be compiled for the target architecture, do we?

I don't know about that but I do know we have image files that can be  
booted in various guest. These image files could include tests like  
the floating point test.

Here is the link to the test images page:
http://wiki.qemu.org/Testing/System_Images

Re: [Qemu-devel] [Qemu-ppc] Floating point unit bugs

[Peter Maydell]

On 21 June 2017 at 17:27, G 3 <programmingkidx@gmail.com> wrote:
> On Jun 21, 2017, at 12:20 PM, Peter Maydell wrote:
>> We don't yet have any mechanism for having tests that need to
>> be compiled for the target architecture, do we?
>
>
> I don't know about that but I do know we have image files that can be booted
> in various guest. These image files could include tests like the floating
> point test.
>
> Here is the link to the test images page:
> http://wiki.qemu.org/Testing/System_Images

Yes -- those are almost all very out of date, not reproducible
at all and don't cover very many of our systems, because we
don't have a good mechanism for writing tests that need
to be built for the target architecture. I'd like us to
have a setup so that it's easy to say "just add a new test",
rather than accumulating more random images on the wiki...

thanks
-- PMM

Re: [Qemu-devel] [Qemu-ppc] Floating point unit bugs

[G 3]

On Jun 21, 2017, at 12:28 PM, Peter Maydell wrote:

> On 21 June 2017 at 17:27, G 3 <programmingkidx@gmail.com> wrote:
>> On Jun 21, 2017, at 12:20 PM, Peter Maydell wrote:
>>> We don't yet have any mechanism for having tests that need to
>>> be compiled for the target architecture, do we?
>>
>>
>> I don't know about that but I do know we have image files that can  
>> be booted
>> in various guest. These image files could include tests like the  
>> floating
>> point test.
>>
>> Here is the link to the test images page:
>> http://wiki.qemu.org/Testing/System_Images
>
> Yes -- those are almost all very out of date, not reproducible
> at all and don't cover very many of our systems, because we
> don't have a good mechanism for writing tests that need
> to be built for the target architecture. I'd like us to
> have a setup so that it's easy to say "just add a new test",
> rather than accumulating more random images on the wiki...

The advantage a test image would have is the user doesn't have to  
worry about compiling a test using a cross compiler. Everything the  
user would need to test QEMU is already inside the image file  
(hopefully).

Is the setup you want something like running 'make test' ? I imagine  
binary files included with QEMU would test the emulated CPU. There  
would be no need to cross compile anything. 

Re: [Qemu-devel] [Qemu-ppc] Floating point unit bugs

[Peter Maydell]

On 22 June 2017 at 03:54, G 3 <programmingkidx@gmail.com> wrote:
> The advantage a test image would have is the user doesn't have to worry
> about compiling a test using a cross compiler. Everything the user would
> need to test QEMU is already inside the image file (hopefully).
>
> Is the setup you want something like running 'make test' ? I imagine binary
> files included with QEMU would test the emulated CPU. There would be no need
> to cross compile anything.

I want our tests to be easy to add new tests for, and easy
for anybody to recreate the binary files. Certainly providing
pre-built binaries would be helpful (faster than rebuilding
whole system images), but we must have an automated mechanism
for saying "build this image from sources" too, so that if
we want to update the test program later it's easy to do that,
or if we want to add a second test that's like the first
one but slightly modified we can easily do that too.

thanks
-- PMM

Re: [Qemu-devel] [Qemu-ppc] Floating point unit bugs

[G 3]

On Jun 22, 2017, at 3:25 AM, Peter Maydell wrote:

> On 22 June 2017 at 03:54, G 3 <programmingkidx@gmail.com> wrote:
>> The advantage a test image would have is the user doesn't have to  
>> worry
>> about compiling a test using a cross compiler. Everything the user  
>> would
>> need to test QEMU is already inside the image file (hopefully).
>>
>> Is the setup you want something like running 'make test' ? I  
>> imagine binary
>> files included with QEMU would test the emulated CPU. There would  
>> be no need
>> to cross compile anything.
>
> I want our tests to be easy to add new tests for, and easy
> for anybody to recreate the binary files. Certainly providing
> pre-built binaries would be helpful (faster than rebuilding
> whole system images), but we must have an automated mechanism
> for saying "build this image from sources" too, so that if
> we want to update the test program later it's easy to do that,
> or if we want to add a second test that's like the first
> one but slightly modified we can easily do that too.

So what you want is a test system that is easy to write. Maybe as  
easy as writing a python script? What I thought up is a collection of  
functions that implement assembly language code. Say you want to make  
a test that runs the fadds instruction. You might run it like this:

def my_float_test:
	inputA = 0.5
	inputB = 0.25
	result = fadds(inputA, inputB)
	if result != 0.75:
		print("Error with fadds calculation")
	if get_FPSCR() != expect_fpscr_value:
		print("FPSCR error")


Then all we would be left to figure out is how to turn this code into  
a mach-o or elf binary. Then again this might not be a requirement.  
What if we had python running on the guest. The above code might work  
as is. No cross compiling required.

Implementing the callable assembly language code from python could be  
done using a single command-line program. This program would simply  
receive its arguments and return a value. If this program was called  
assembly _adapter, it would run like this:

% assembly_adapter fadds 0.5 0.25

The return value of this command is where we would see the result.  
This command-line program would only need to be compiled once and  
included with QEMU. The format of this program's arguments would be  
something like this:  <assembly instruction> <input> <input>

This input would probably work for most instructions but doesn't  
necessarily need to be applied to all instructions.

Would this kind of system be something you want? 

Re: [Qemu-devel] [Qemu-ppc] Floating point unit bugs

[Alex Bennée]

Peter Maydell <peter.maydell@linaro.org> writes:

> On 21 June 2017 at 17:14, Philippe Mathieu-Daudé <f4bug@amsat.org> wrote:
>> do you think you can add your test as a qtest, to run it with check-qtest?
>
> We don't yet have any mechanism for having tests that need to
> be compiled for the target architecture, do we?

I posted a proof of concept a while ago:

  Subject: [RFC/POC PATCH 0/4] Building TCG tests with emdebian cross compilers
  Date: Wed, 14 Dec 2016 17:12:40 +0000
  Message-Id: <20161214171244.26813-1-alex.bennee@linaro.org>

And I think Pranith respun his TCG tests cleanup with them. But that
work isn't merged yet.

>
> thanks
> -- PMM


--
Alex Bennée

Re: [Qemu-devel] [Qemu-ppc] Floating point unit bugs

[G 3]

On Jun 21, 2017, at 12:14 PM, Philippe Mathieu-Daudé wrote:

> Hi John,
>
> On 05/09/2017 10:58 AM, G 3 wrote:
>>
>> On May 9, 2017, at 5:55 AM, BALATON Zoltan wrote:
>>
>>> On Tue, 9 May 2017, Aurelien Jarno wrote:
>>>> | main.c: In function 'print_fpscr_settings':
>>>> | main.c:73:26: warning: suggest parentheses around comparison in
>>>> operand of '&' [-Wparentheses]
>>>> |          if ((fpscr >> i) & 0x1 == 1) {
>>>> |                           ^
>>>
>>> Actually the compiler is correct here, this should be:
>>>
>>> if ((fpscr >> i & 0x1) == 1) {
>>>
>>> or even just
>>>
>>> if (fpscr >> i & 1) {
>>>
>>> because & is lower priority than == but the result may still be the
>>> same by chance if 0x1 == 1 is always 1 and ANDing the shifted value
>>> with this is either 0 or 1 so it may give the correct result but not
>>> the way one would think looking at the expression.
>>
>> I changed it to this:
>> if (((fpscr >> i) & 0x1) == 1)
>>
>> Thank you.
>
> do you think you can add your test as a qtest, to run it with check- 
> qtest?
>
> Regards,
>
> Phil.

I would like to see floating point tests added to QEMU. Problem is  
they will always fail due to a ton of bugs with the floating point unit.