# HG changeset patch
# User Keir Fraser <keir.fraser@xxxxxxxxxx>
# Date 1208360567 -3600
# Node ID a38a41de0800cefca755ffb600d6d5e96f084697
# Parent defbab4dba1a40ce08ed5b9331cfaf7a4422853e
x86_emulate: Emulate certain FPU instructions by building the opcode
on the stack. This allows us to add emulation for a number of extra
FPU opcodes without inflating the executable code size.
Signed-off-by: Keir Fraser <keir.fraser@xxxxxxxxxx>
---
xen/arch/x86/x86_emulate/x86_emulate.c | 89 ++++++++++++++++++++++-----------
1 files changed, 60 insertions(+), 29 deletions(-)
diff -r defbab4dba1a -r a38a41de0800 xen/arch/x86/x86_emulate/x86_emulate.c
--- a/xen/arch/x86/x86_emulate/x86_emulate.c Wed Apr 16 16:10:41 2008 +0100
+++ b/xen/arch/x86/x86_emulate/x86_emulate.c Wed Apr 16 16:42:47 2008 +0100
@@ -558,7 +558,7 @@ static void fpu_handle_exception(void *_
regs->eip += fic->insn_bytes;
}
-#define __emulate_fpu_insn(_op) \
+#define emulate_fpu_insn(_op) \
do{ struct fpu_insn_ctxt fic = { 0 }; \
fail_if(ops->get_fpu == NULL); \
ops->get_fpu(fpu_handle_exception, &fic, ctxt); \
@@ -571,7 +571,7 @@ do{ struct fpu_insn_ctxt fic = { 0 };
generate_exception_if(fic.exn_raised, EXC_MF, -1); \
} while (0)
-#define __emulate_fpu_insn_memdst(_op, _arg) \
+#define emulate_fpu_insn_memdst(_op, _arg) \
do{ struct fpu_insn_ctxt fic = { 0 }; \
fail_if(ops->get_fpu == NULL); \
ops->get_fpu(fpu_handle_exception, &fic, ctxt); \
@@ -583,6 +583,16 @@ do{ struct fpu_insn_ctxt fic = { 0 };
: : "memory" ); \
ops->put_fpu(ctxt); \
generate_exception_if(fic.exn_raised, EXC_MF, -1); \
+} while (0)
+
+#define emulate_fpu_insn_stub(_bytes...) \
+do{ uint8_t stub[] = { _bytes, 0xc3 }; \
+ struct fpu_insn_ctxt fic = { .insn_bytes = sizeof(stub)-1 }; \
+ fail_if(ops->get_fpu == NULL); \
+ ops->get_fpu(fpu_handle_exception, &fic, ctxt); \
+ (*(void(*)(void))stub)(); \
+ ops->put_fpu(ctxt); \
+ generate_exception_if(fic.exn_raised, EXC_MF, -1); \
} while (0)
static unsigned long __get_rep_prefix(
@@ -2438,7 +2448,7 @@ x86_emulate(
}
case 0x9b: /* wait/fwait */
- __emulate_fpu_insn("fwait");
+ emulate_fpu_insn("fwait");
break;
case 0x9c: /* pushf */
@@ -2760,32 +2770,52 @@ x86_emulate(
case 0xd9: /* FPU 0xd9 */
switch ( modrm )
{
- case 0xc0: __emulate_fpu_insn(".byte 0xd9,0xc0"); break; /* fld %st0 */
- case 0xc1: __emulate_fpu_insn(".byte 0xd9,0xc1"); break; /* fld %st1 */
- case 0xc2: __emulate_fpu_insn(".byte 0xd9,0xc2"); break; /* fld %st2 */
- case 0xc3: __emulate_fpu_insn(".byte 0xd9,0xc3"); break; /* fld %st3 */
- case 0xc4: __emulate_fpu_insn(".byte 0xd9,0xc4"); break; /* fld %st4 */
- case 0xc5: __emulate_fpu_insn(".byte 0xd9,0xc5"); break; /* fld %st5 */
- case 0xc6: __emulate_fpu_insn(".byte 0xd9,0xc6"); break; /* fld %st6 */
- case 0xc7: __emulate_fpu_insn(".byte 0xd9,0xc7"); break; /* fld %st7 */
- case 0xe0: __emulate_fpu_insn(".byte 0xd9,0xe0"); break; /* fchs */
- case 0xe1: __emulate_fpu_insn(".byte 0xd9,0xe1"); break; /* fabs */
- case 0xe8: __emulate_fpu_insn(".byte 0xd9,0xe8"); break; /* fld1 */
- case 0xee: __emulate_fpu_insn(".byte 0xd9,0xee"); break; /* fldz */
+ case 0xc0 ... 0xc7: /* fld %stN */
+ case 0xc8 ... 0xcf: /* fxch %stN */
+ case 0xd0: /* fnop */
+ case 0xe0: /* fchs */
+ case 0xe1: /* fabs */
+ case 0xe4: /* ftst */
+ case 0xe5: /* fxam */
+ case 0xe8: /* fld1 */
+ case 0xe9: /* fldl2t */
+ case 0xea: /* fldl2e */
+ case 0xeb: /* fldpi */
+ case 0xec: /* fldlg2 */
+ case 0xed: /* fldln2 */
+ case 0xee: /* fldz */
+ case 0xf0: /* f2xm1 */
+ case 0xf1: /* fyl2x */
+ case 0xf2: /* fptan */
+ case 0xf3: /* fpatan */
+ case 0xf4: /* fxtract */
+ case 0xf5: /* fprem1 */
+ case 0xf6: /* fdecstp */
+ case 0xf7: /* fincstp */
+ case 0xf8: /* fprem */
+ case 0xf9: /* fyl2xp1 */
+ case 0xfa: /* fsqrt */
+ case 0xfb: /* fsincos */
+ case 0xfc: /* frndint */
+ case 0xfd: /* fscale */
+ case 0xfe: /* fsin */
+ case 0xff: /* fcos */
+ emulate_fpu_insn_stub(0xd9, modrm);
+ break;
default:
fail_if((modrm_reg & 7) != 7);
fail_if(modrm >= 0xc0);
/* fnstcw m2byte */
ea.bytes = 2;
dst = ea;
- __emulate_fpu_insn_memdst("fnstcw", dst.val);
+ emulate_fpu_insn_memdst("fnstcw", dst.val);
}
break;
case 0xdb: /* FPU 0xdb */
fail_if(modrm != 0xe3);
/* fninit */
- __emulate_fpu_insn("fninit");
+ emulate_fpu_insn("fninit");
break;
case 0xdd: /* FPU 0xdd */
@@ -2794,22 +2824,23 @@ x86_emulate(
/* fnstsw m2byte */
ea.bytes = 2;
dst = ea;
- __emulate_fpu_insn_memdst("fnstsw", dst.val);
+ emulate_fpu_insn_memdst("fnstsw", dst.val);
break;
case 0xde: /* FPU 0xde */
switch ( modrm )
{
- case 0xd9: __emulate_fpu_insn(".byte 0xde,0xd9"); break;
- case 0xf8: __emulate_fpu_insn(".byte 0xde,0xf8"); break;
- case 0xf9: __emulate_fpu_insn(".byte 0xde,0xf9"); break;
- case 0xfa: __emulate_fpu_insn(".byte 0xde,0xfa"); break;
- case 0xfb: __emulate_fpu_insn(".byte 0xde,0xfb"); break;
- case 0xfc: __emulate_fpu_insn(".byte 0xde,0xfc"); break;
- case 0xfd: __emulate_fpu_insn(".byte 0xde,0xfd"); break;
- case 0xfe: __emulate_fpu_insn(".byte 0xde,0xfe"); break;
- case 0xff: __emulate_fpu_insn(".byte 0xde,0xff"); break;
- default: goto cannot_emulate;
+ case 0xc0 ... 0xc7: /* faddp %stN */
+ case 0xc8 ... 0xcf: /* fmulp %stN */
+ case 0xd9: /* fcompp */
+ case 0xe0 ... 0xe7: /* fsubrp %stN */
+ case 0xe8 ... 0xef: /* fsubp %stN */
+ case 0xf0 ... 0xf7: /* fdivrp %stN */
+ case 0xf8 ... 0xff: /* fdivp %stN */
+ emulate_fpu_insn_stub(0xde, modrm);
+ break;
+ default:
+ goto cannot_emulate;
}
break;
@@ -2819,7 +2850,7 @@ x86_emulate(
dst.bytes = 2;
dst.type = OP_REG;
dst.reg = (unsigned long *)&_regs.eax;
- __emulate_fpu_insn_memdst("fnstsw", dst.val);
+ emulate_fpu_insn_memdst("fnstsw", dst.val);
break;
case 0xe0 ... 0xe2: /* loop{,z,nz} */ {
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