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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-changelog] [xen-unstable] [XEN] Emulate DAA/DAS the hard way. We cannot execute the instruction
# HG changeset patch
# User kfraser@xxxxxxxxxxxxxxxxxxxxx
# Date 1168361992 0
# Node ID c98f3f3f7099ec1516354faa34a16be841e4a47c
# Parent de6b5a76d680057c7793561c40a9285c613065d1
[XEN] Emulate DAA/DAS the hard way. We cannot execute the instruction
directly within the emulator as it is unavailable if the emulator runs
in x86/64 mode.
Signed-off-by: Keir Fraser <keir@xxxxxxxxxxxxx>
---
tools/tests/test_x86_emulator.c | 67 ++++++++++++++++++++++++++++++++++++++--
xen/arch/x86/x86_emulate.c | 46 ++++++++++++++++++++-------
2 files changed, 99 insertions(+), 14 deletions(-)
diff -r de6b5a76d680 -r c98f3f3f7099 tools/tests/test_x86_emulator.c
--- a/tools/tests/test_x86_emulator.c Tue Jan 09 16:49:16 2007 +0000
+++ b/tools/tests/test_x86_emulator.c Tue Jan 09 16:59:52 2007 +0000
@@ -15,6 +15,15 @@ typedef int64_t s64;
#include <asm-x86/x86_emulate.h>
#include <sys/mman.h>
+/* EFLAGS bit definitions. */
+#define EFLG_OF (1<<11)
+#define EFLG_DF (1<<10)
+#define EFLG_SF (1<<7)
+#define EFLG_ZF (1<<6)
+#define EFLG_AF (1<<4)
+#define EFLG_PF (1<<2)
+#define EFLG_CF (1<<0)
+
static int read(
unsigned int seg,
unsigned long offset,
@@ -98,8 +107,8 @@ int main(int argc, char **argv)
struct x86_emulate_ctxt ctxt;
struct cpu_user_regs regs;
char instr[20] = { 0x01, 0x08 }; /* add %ecx,(%eax) */
- unsigned int *res;
- int rc;
+ unsigned int *res, bcdres_native, bcdres_emul;
+ int rc, i;
ctxt.regs = ®s;
ctxt.address_bytes = 4;
@@ -399,6 +408,60 @@ int main(int argc, char **argv)
goto fail;
printf("okay\n");
+ printf("%-40s", "Testing daa/das (all inputs)...");
+ /* Bits 0-7: AL; Bit 8: EFLG_AF; Bit 9: EFLG_CF; Bit 10: DAA vs. DAS. */
+ for ( i = 0; i < 0x800; i++ )
+ {
+ regs.eflags = (i & 0x200) ? EFLG_CF : 0;
+ regs.eflags |= (i & 0x100) ? EFLG_AF : 0;
+ if ( i & 0x400 )
+ __asm__ (
+ "pushf; and $0xffffffee,(%%esp); or %1,(%%esp); popf; das; "
+ "pushf; popl %1"
+ : "=a" (bcdres_native), "=r" (regs.eflags)
+ : "0" (i & 0xff), "1" (regs.eflags) );
+ else
+ __asm__ (
+ "pushf; and $0xffffffee,(%%esp); or %1,(%%esp); popf; daa; "
+ "pushf; popl %1"
+ : "=a" (bcdres_native), "=r" (regs.eflags)
+ : "0" (i & 0xff), "1" (regs.eflags) );
+ bcdres_native |= (regs.eflags & EFLG_CF) ? 0x200 : 0;
+ bcdres_native |= (regs.eflags & EFLG_AF) ? 0x100 : 0;
+
+ instr[0] = (i & 0x400) ? 0x2f: 0x27; /* daa/das */
+ regs.eflags = (i & 0x200) ? EFLG_CF : 0;
+ regs.eflags |= (i & 0x100) ? EFLG_AF : 0;
+ regs.eip = (unsigned long)&instr[0];
+ regs.eax = (unsigned char)i;
+ rc = x86_emulate(&ctxt, &emulops);
+ bcdres_emul = regs.eax;
+ bcdres_emul |= (regs.eflags & EFLG_CF) ? 0x200 : 0;
+ bcdres_emul |= (regs.eflags & EFLG_AF) ? 0x100 : 0;
+ if ( (rc != 0) || (regs.eax > 255) ||
+ (regs.eip != (unsigned long)&instr[1]) )
+ goto fail;
+
+ if ( bcdres_emul != bcdres_native )
+ {
+ printf("%s: AL=%02x %s %s\n"
+ "Output: AL=%02x %s %s\n"
+ "Emul.: AL=%02x %s %s\n",
+ (i & 0x400) ? "DAS" : "DAA",
+ (unsigned char)i,
+ (i & 0x200) ? "CF" : " ",
+ (i & 0x100) ? "AF" : " ",
+ (unsigned char)bcdres_native,
+ (bcdres_native & 0x200) ? "CF" : " ",
+ (bcdres_native & 0x100) ? "AF" : " ",
+ (unsigned char)bcdres_emul,
+ (bcdres_emul & 0x200) ? "CF" : " ",
+ (bcdres_emul & 0x100) ? "AF" : " ");
+ goto fail;
+ }
+ }
+ printf("okay\n");
+
return 0;
fail:
diff -r de6b5a76d680 -r c98f3f3f7099 xen/arch/x86/x86_emulate.c
--- a/xen/arch/x86/x86_emulate.c Tue Jan 09 16:49:16 2007 +0000
+++ b/xen/arch/x86/x86_emulate.c Tue Jan 09 16:59:52 2007 +0000
@@ -1174,25 +1174,47 @@ x86_emulate(
{
case 0x27: /* daa */ {
uint8_t al = _regs.eax;
- unsigned long tmp;
+ unsigned long eflags = _regs.eflags;
fail_if(mode_64bit());
- __asm__ __volatile__ (
- _PRE_EFLAGS("0","4","2") "daa; " _POST_EFLAGS("0","4","2")
- : "=m" (_regs.eflags), "=a" (al), "=&r" (tmp)
- : "a" (al), "i" (EFLAGS_MASK) );
- *(uint8_t *)_regs.eax = al;
+ _regs.eflags &= ~(EFLG_CF|EFLG_AF);
+ if ( ((al & 0x0f) > 9) || (eflags & EFLG_AF) )
+ {
+ *(uint8_t *)&_regs.eax += 6;
+ _regs.eflags |= EFLG_AF;
+ }
+ if ( (al > 0x99) || (eflags & EFLG_CF) )
+ {
+ *(uint8_t *)&_regs.eax += 0x60;
+ _regs.eflags |= EFLG_CF;
+ }
+ _regs.eflags &= ~(EFLG_SF|EFLG_ZF|EFLG_PF);
+ _regs.eflags |= ((uint8_t)_regs.eax == 0) ? EFLG_ZF : 0;
+ _regs.eflags |= (( int8_t)_regs.eax < 0) ? EFLG_SF : 0;
+ _regs.eflags |= even_parity(_regs.eax) ? EFLG_PF : 0;
break;
}
case 0x2f: /* das */ {
uint8_t al = _regs.eax;
- unsigned long tmp;
+ unsigned long eflags = _regs.eflags;
fail_if(mode_64bit());
- __asm__ __volatile__ (
- _PRE_EFLAGS("0","4","2") "das; " _POST_EFLAGS("0","4","2")
- : "=m" (_regs.eflags), "=a" (al), "=&r" (tmp)
- : "a" (al), "i" (EFLAGS_MASK) );
- *(uint8_t *)_regs.eax = al;
+ _regs.eflags &= ~(EFLG_CF|EFLG_AF);
+ if ( ((al & 0x0f) > 9) || (eflags & EFLG_AF) )
+ {
+ _regs.eflags |= EFLG_AF;
+ if ( (al < 6) || (eflags & EFLG_CF) )
+ _regs.eflags |= EFLG_CF;
+ *(uint8_t *)&_regs.eax -= 6;
+ }
+ if ( (al > 0x99) || (eflags & EFLG_CF) )
+ {
+ *(uint8_t *)&_regs.eax -= 0x60;
+ _regs.eflags |= EFLG_CF;
+ }
+ _regs.eflags &= ~(EFLG_SF|EFLG_ZF|EFLG_PF);
+ _regs.eflags |= ((uint8_t)_regs.eax == 0) ? EFLG_ZF : 0;
+ _regs.eflags |= (( int8_t)_regs.eax < 0) ? EFLG_SF : 0;
+ _regs.eflags |= even_parity(_regs.eax) ? EFLG_PF : 0;
break;
}
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