Re: [Qemu-devel] [SPARC][PATCH] Generate cp_disabled trap for Cpop instructions

[Aurelien Jarno <aurelien@aurel32.net>]

On Fri, Mar 30, 2007 at 07:18:28PM +0200, Aurelien Jarno wrote:
> Hi all,
> 
> Both of the SPARC CPU currently emulated in QEMU do not have a 
> coprocessor. In such case executing a Cpop1 or a Cpop2 instruction 
> should generate a cp_disabled trap, but the current implementation
> generates a illegal_instruction instead.
> 

This is actually wrong for the SPARCv9 target. Those instructions have
been removed from the SPARCv9 instruction set, so they should generate
an illegal_instruction trap on SPARCv9 and a cp_disabled trap on
SPARCv8.

The patch below is now correct. It also does the same for LDC* and STC*
instructions.

Index: target-sparc/cpu.h
===================================================================
RCS file: /sources/qemu/qemu/target-sparc/cpu.h,v
retrieving revision 1.30
diff -u -d -p -r1.30 cpu.h
--- target-sparc/cpu.h	25 Mar 2007 07:55:52 -0000	1.30
+++ target-sparc/cpu.h	31 Mar 2007 12:29:24 -0000
@@ -40,6 +40,7 @@
 #define TT_TOVF     0x0a
 #define TT_EXTINT   0x10
 #define TT_DIV_ZERO 0x2a
+#define TT_NCP_INSN 0x24
 #define TT_TRAP     0x80
 #else
 #define TT_TFAULT   0x08
Index: target-sparc/translate.c
===================================================================
RCS file: /sources/qemu/qemu/target-sparc/translate.c,v
retrieving revision 1.38
diff -u -d -p -r1.38 translate.c
--- target-sparc/translate.c	25 Mar 2007 07:55:52 -0000	1.38
+++ target-sparc/translate.c	31 Mar 2007 12:29:25 -0000
@@ -1736,7 +1739,7 @@ static void disas_sparc_insn(DisasContex
 		    gen_op_sra();
 		gen_movl_T0_reg(rd);
 #endif
-	    } else if (xop < 0x38) {
+	    } else if (xop < 0x36) {
                 rs1 = GET_FIELD(insn, 13, 17);
 		gen_movl_reg_T0(rs1);
 		if (IS_IMM) {	/* immediate */
@@ -2142,6 +2145,12 @@ static void disas_sparc_insn(DisasContex
 			goto illegal_insn;
 		    }
 		}
+	    } else if (xop == 0x36 || xop == 0x37) { /* CPop1 & CPop2, V9 impdep1 & impdep2 */
+#ifdef TARGET_SPARC64
+		goto illegal_insn;
+#else
+		goto ncp_insn;
+#endif
 #ifdef TARGET_SPARC64
 	    } else if (xop == 0x39) { /* V9 return */
                 rs1 = GET_FIELD(insn, 13, 17);
@@ -2390,6 +2415,17 @@ static void disas_sparc_insn(DisasContex
 		    break;
 
 #ifndef TARGET_SPARC64
+		case 0x30: /* ldc */
+		case 0x31: /* ldcsr */
+		case 0x33: /* lddc */
+		case 0x34: /* stc */
+		case 0x35: /* stcsr */
+		case 0x36: /* stdcq */
+		case 0x37: /* stdc */
+		    goto ncp_insn;
+		    break;
+#endif		   
+#ifndef TARGET_SPARC64
                     /* avoid warnings */
                     (void) &gen_op_stfa;
                     (void) &gen_op_stdfa;
@@ -2598,6 +2648,12 @@ static void disas_sparc_insn(DisasContex
     save_state(dc);
     gen_op_fpexception_im(FSR_FTT_UNIMPFPOP);
     dc->is_br = 1;
+#ifndef TARGET_SPARC64
+ ncp_insn:
+    save_state(dc);
+    gen_op_exception(TT_NCP_INSN);
+    dc->is_br = 1;
+#endif
 }
 
 static inline int gen_intermediate_code_internal(TranslationBlock * tb,

-- 
  .''`.  Aurelien Jarno	            | GPG: 1024D/F1BCDB73
 : :' :  Debian developer           | Electrical Engineer
 `. `'   aurel32@debian.org         | aurelien@aurel32.net
   `-    people.debian.org/~aurel32 | www.aurel32.net