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authoriximeow <me@iximeow.net>2026-06-05 08:32:09 +0000
committeriximeow <me@iximeow.net>2026-06-21 16:44:21 +0000
commite38dbea8cb456758c50f3593287acdca3983889e (patch)
treee6abc5573a21ee8f6eb6754d83aab846b0f72e32 /src/real_mode/mod.rs
parenta38cba0c4a4ed9a1ed763618e5efe3f4487b1ad0 (diff)
fix several instructions' incorrect memory or op2 size
Diffstat (limited to 'src/real_mode/mod.rs')
-rw-r--r--src/real_mode/mod.rs13
1 files changed, 9 insertions, 4 deletions
diff --git a/src/real_mode/mod.rs b/src/real_mode/mod.rs
index 716148c..334c07a 100644
--- a/src/real_mode/mod.rs
+++ b/src/real_mode/mod.rs
@@ -6686,7 +6686,7 @@ fn read_operands<
if instruction.operands[1] != OperandSpec::RegMMM {
if [Opcode::PMOVSXBQ, Opcode::PMOVZXBQ].contains(&instruction.opcode) {
instruction.mem_size = 2;
- } else if [Opcode::PMOVZXBD, Opcode::UCOMISS, Opcode::COMISS, Opcode::CVTSS2SD].contains(&instruction.opcode) {
+ } else if [Opcode::PMOVZXBD, Opcode::PMOVSXBD, Opcode::PMOVZXWQ, Opcode::PMOVSXWQ, Opcode::UCOMISS, Opcode::COMISS, Opcode::CVTSS2SD].contains(&instruction.opcode) {
instruction.mem_size = 4;
} else {
instruction.mem_size = 8;
@@ -7435,6 +7435,7 @@ fn read_operands<
}
7 => {
instruction.opcode = Opcode::RDPID;
+ // > "The value of CS.D and operand-size prefixes (66H and REX.W) do not affect the behavior of the RDPID instruction."
instruction.operands[0] = read_E(words, instruction, modrm, RegisterBank::D, sink)?;
if instruction.operands[0] != OperandSpec::RegMMM {
return Err(DecodeError::InvalidOperand);
@@ -8336,12 +8337,16 @@ fn read_operands<
instruction.operands[0] = read_E(words, instruction, modrm, bank, sink)?;
}
} else if r == 4 {
- // TODO: this permits storing only to word-size registers
- // spec suggets this might do something different for f.ex rdi?
+ // TODO: note that this was incorrectly choosing 16-bit operands every time
instruction.opcode = Opcode::SMSW;
instruction.operand_count = 1;
instruction.mem_size = 2;
- instruction.operands[0] = read_E(words, instruction, modrm, RegisterBank::W, sink)?;
+ let bank = if !instruction.prefixes.operand_size() {
+ RegisterBank::W
+ } else {
+ RegisterBank::D
+ };
+ instruction.operands[0] = read_E(words, instruction, modrm, bank, sink)?;
} else if r == 5 {
let mod_bits = modrm >> 6;
if mod_bits != 0b11 {