Re: [Qemu-devel] Running QEMU on FreeBSD

[Antony T Curtis <antony.t.curtis@ntlworld.com>]

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On Mon, 2004-05-31 at 02:42, Bartosz Fabianowski wrote:
> This fixes the NaN, but reverts to what my hack did - weird rounding. 
> The total download size for some updates I selected is now reported as 
> 1.6000000000000003 (that's 14 zeros in between). Not quite sure what's 
> going wrong here...

Ok... I am curious if the following diff helps it (or makes it worse)
It is just a quick hack to use the native fpu instructions instead of
manual calculation...

-- 
Antony T Curtis <antony.t.curtis@ntlworld.com>

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--- /home/antony/cvs/qemu/target-i386/helper.c	Sat May 29 12:08:52 2004
+++ target-i386/helper.c	Mon May 31 15:40:13 2004
@@ -2105,7 +2105,12 @@
 
 void helper_f2xm1(void)
 {
+#ifdef USE_X86LDOUBLE
+    __asm __volatile__
+      ("f2xm1" : "=t" (ST0) : "0" (ST0));
+#else
     ST0 = pow(2.0,ST0) - 1.0;
+#endif
 }
 
 void helper_fyl2x(void)
@@ -2114,8 +2119,14 @@
     
     fptemp = ST0;
     if (fptemp>0.0){
+#ifdef USE_X86LDOUBLE
+        __asm __volatile__
+          ("fyl2x"
+           : "=t" (ST1) : "0" (fptemp) , "u" (ST1));
+#else
         fptemp = log(fptemp)/log(2.0);	 /* log2(ST) */
         ST1 *= fptemp;
+#endif
         fpop();
     } else { 
         env->fpus &= (~0x4700);
@@ -2165,6 +2176,19 @@
 
 void helper_fprem1(void)
 {
+#ifdef USE_X86LDOUBLE
+    int flags;
+    __asm __volatile__
+      ("fprem1\n\t"
+       "fnstsw %%ax\n\t"
+       : "=t" (ST0), "=ax" (flags) : "0" (ST0) , "u" (ST1));
+    if (flags & 0x400) 
+        env->fpus |= 0x400;
+    else {
+        env->fpus &= (~0x4700);
+        env->fpus |= flags & 0x07;
+    }
+#else
     CPU86_LDouble dblq, fpsrcop, fptemp;
     CPU86_LDoubleU fpsrcop1, fptemp1;
     int expdif;
@@ -2194,10 +2218,24 @@
             floor(fpsrcop): ceil(fpsrcop);
         ST0 -= (ST1 * fpsrcop * fptemp);
     }
+#endif
 }
 
 void helper_fprem(void)
 {
+#ifdef USE_X86LDOUBLE
+    int flags;
+    __asm __volatile__
+      ("fprem\n\t"
+       "fnstsw %%ax\n\t"
+       : "=t" (ST0), "=ax" (flags) : "0" (ST0) , "u" (ST1));
+    if (flags & 0x400) 
+        env->fpus |= 0x400;
+    else {
+        env->fpus &= (~0x4700);
+        env->fpus |= flags & 0x07;
+    }
+#else
     CPU86_LDouble dblq, fpsrcop, fptemp;
     CPU86_LDoubleU fpsrcop1, fptemp1;
     int expdif;
@@ -2205,6 +2243,7 @@
     
     fpsrcop = ST0;
     fptemp = ST1;
+
     fpsrcop1.d = fpsrcop;
     fptemp1.d = fptemp;
     expdif = EXPD(fpsrcop1) - EXPD(fptemp1);
@@ -2227,6 +2266,7 @@
             -(floor(fabs(fpsrcop))): floor(fpsrcop);
         ST0 -= (ST1 * fpsrcop * fptemp);
     }
+#endif
 }
 
 void helper_fyl2xp1(void)
@@ -2235,8 +2275,13 @@
 
     fptemp = ST0;
     if ((fptemp+1.0)>0.0) {
+#ifdef USE_X86LDOUBLE
+        __asm __volatile__
+          ("fyl2xp1" : "=t" (ST1) : "0" (fptemp) , "u" (ST1));
+#else
         fptemp = log(fptemp+1.0) / log(2.0); /* log2(ST+1.0) */
         ST1 *= fptemp;
+#endif
         fpop();
     } else { 
         env->fpus &= (~0x4700);
@@ -2264,11 +2309,17 @@
     if ((fptemp > MAXTAN)||(fptemp < -MAXTAN)) {
         env->fpus |= 0x400;
     } else {
+#ifdef USE_X86LDOUBLE
+        __asm __volatile__
+          ("fsincos" 
+           : "=t" (ST0) , "=u" (ST1) : "0" (ST0));
+#else
         ST0 = sin(fptemp);
         fpush();
         ST0 = cos(fptemp);
         env->fpus &= (~0x400);  /* C2 <-- 0 */
         /* the above code is for  |arg| < 2**63 only */
+#endif
     }
 }
 
@@ -2301,11 +2352,18 @@
 
 void helper_fscale(void)
 {
+#ifdef USE_X86LDOUBLE
+    __asm __volatile__
+      ("fscale" 
+       : "=t" (ST0) : "0" (ST0), "u" (ST1));
+#else
     CPU86_LDouble fpsrcop, fptemp;
 
     fpsrcop = 2.0;
     fptemp = pow(fpsrcop,ST1);
     ST0 *= fptemp;
+#endif
+
 }
 
 void helper_fsin(void)