diff options
| -rw-r--r-- | subx/011direct_addressing.cc | 21 |
1 files changed, 21 insertions, 0 deletions
diff --git a/subx/011direct_addressing.cc b/subx/011direct_addressing.cc index 9e5f6e80..58576a42 100644 --- a/subx/011direct_addressing.cc +++ b/subx/011direct_addressing.cc @@ -215,6 +215,27 @@ case 0x89: { // copy r32 to r/m32 break; } +//:: xchg + +:(scenario xchg_r32_with_r32) +% Reg[3].i = 0xaf; +# op ModRM SIB displacement immediate + 87 d8 # exchange EBX (reg 3) with EAX (reg 0) ++run: exchange reg 3 with effective address ++run: effective address is reg 0 ++run: storing 0x000000af + +:(before "End Single-Byte Opcodes") +case 0x87: { // exchange r32 with r/m32 + uint8_t modrm = next(); + uint8_t reg2 = (modrm>>3)&0x7; + trace(2, "run") << "exchange reg " << NUM(reg2) << " with effective address" << end(); + int32_t* arg1 = effective_address(modrm); + *arg1 = Reg[reg2].i; + trace(2, "run") << "storing 0x" << HEXWORD << *arg1 << end(); + break; +} + //:: push :(scenario push_r32) |