1.1 --- a/tools/tests/test_x86_emulator.c	Fri Dec 01 13:55:28 2006 +0000
     1.2 +++ b/tools/tests/test_x86_emulator.c	Fri Dec 01 13:57:46 2006 +0000
     1.3 @@ -304,6 +304,7 @@ int main(int argc, char **argv)
     1.4  
     1.5      printf("%-40s", "Testing cmpxchg8b (%edi) [failing]...");
     1.6      instr[0] = 0x0f; instr[1] = 0xc7; instr[2] = 0x0f;
     1.7 +    regs.eflags = 0x200;
     1.8      regs.eip    = (unsigned long)&instr[0];
     1.9      regs.edi    = (unsigned long)res;
    1.10      regs.error_code = PFEC_write_access;
    1.11 @@ -320,6 +321,7 @@ int main(int argc, char **argv)
    1.12  
    1.13      printf("%-40s", "Testing movsxbd (%%eax),%%ecx...");
    1.14      instr[0] = 0x0f; instr[1] = 0xbe; instr[2] = 0x08;
    1.15 +    regs.eflags = 0x200;
    1.16      regs.eip    = (unsigned long)&instr[0];
    1.17      regs.ecx    = 0x12345678;
    1.18      regs.eax    = (unsigned long)res;
    1.19 @@ -336,6 +338,7 @@ int main(int argc, char **argv)
    1.20  
    1.21      printf("%-40s", "Testing movzxwd (%%eax),%%ecx...");
    1.22      instr[0] = 0x0f; instr[1] = 0xb7; instr[2] = 0x08;
    1.23 +    regs.eflags = 0x200;
    1.24      regs.eip    = (unsigned long)&instr[0];
    1.25      regs.ecx    = 0x12345678;
    1.26      regs.eax    = (unsigned long)res;
    1.27 @@ -350,6 +353,23 @@ int main(int argc, char **argv)
    1.28          goto fail;
    1.29      printf("okay\n");
    1.30  
    1.31 +    printf("%-40s", "Testing xadd %%ax,(%%ecx)...");
    1.32 +    instr[0] = 0x66; instr[1] = 0x0f; instr[2] = 0xc1; instr[3] = 0x01;
    1.33 +    regs.eflags = 0x200;
    1.34 +    regs.eip    = (unsigned long)&instr[0];
    1.35 +    regs.ecx    = (unsigned long)res;
    1.36 +    regs.eax    = 0x12345678;
    1.37 +    *res        = 0x11111111;
    1.38 +    regs.error_code = 0;
    1.39 +    rc = x86_emulate_memop(&ctxt, &emulops);
    1.40 +    if ( (rc != 0) ||
    1.41 +         (*res != 0x11116789) ||
    1.42 +         (regs.eax != 0x12341111) ||
    1.43 +         ((regs.eflags&0x240) != 0x200) ||
    1.44 +         (regs.eip != (unsigned long)&instr[4]) )
    1.45 +        goto fail;
    1.46 +    printf("okay\n");
    1.47 +
    1.48      return 0;
    1.49  
    1.50   fail:

     2.1 --- a/xen/arch/x86/x86_emulate.c	Fri Dec 01 13:55:28 2006 +0000
     2.2 +++ b/xen/arch/x86/x86_emulate.c	Fri Dec 01 13:57:46 2006 +0000
     2.3 @@ -179,8 +179,11 @@ static uint8_t twobyte_table[256] = {
     2.4      /* 0xB8 - 0xBF */
     2.5      0, 0, DstBitBase|SrcImmByte|ModRM, DstBitBase|SrcReg|ModRM,
     2.6      0, 0, ByteOp|DstReg|SrcMem|ModRM|Mov, DstReg|SrcMem16|ModRM|Mov,
     2.7 -    /* 0xC0 - 0xCF */
     2.8 -    0, 0, 0, 0, 0, 0, 0, ImplicitOps|ModRM, 0, 0, 0, 0, 0, 0, 0, 0,
     2.9 +    /* 0xC0 - 0xC7 */
    2.10 +    ByteOp|DstMem|SrcReg|ModRM, DstMem|SrcReg|ModRM, 0, 0,
    2.11 +    0, 0, 0, ImplicitOps|ModRM,
    2.12 +    /* 0xC8 - 0xCF */
    2.13 +    0, 0, 0, 0, 0, 0, 0, 0,
    2.14      /* 0xD0 - 0xDF */
    2.15      0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    2.16      /* 0xE0 - 0xEF */
    2.17 @@ -1116,6 +1119,16 @@ x86_emulate_memop(
    2.18          dst.bytes = op_bytes;
    2.19          dst.val = (d & ByteOp) ? (int8_t)src.val : (int16_t)src.val;
    2.20          break;
    2.21 +    case 0xc0 ... 0xc1: /* xadd */
    2.22 +        /* Write back the register source. */
    2.23 +        switch ( dst.bytes )
    2.24 +        {
    2.25 +        case 1: *(uint8_t  *)src.reg = (uint8_t)dst.val; break;
    2.26 +        case 2: *(uint16_t *)src.reg = (uint16_t)dst.val; break;
    2.27 +        case 4: *src.reg = (uint32_t)dst.val; break; /* 64b reg: zero-extend */
    2.28 +        case 8: *src.reg = dst.val; break;
    2.29 +        }
    2.30 +        goto add;
    2.31      }
    2.32      goto writeback;
    2.33