From ab51fd1b2c7cf1b7bb6f84c5b07e06245f6b3d99 Mon Sep 17 00:00:00 2001 From: iximeow Date: Mon, 24 Jul 2023 06:41:02 -0700 Subject: fix handling of lar/lsl source register --- src/protected_mode/mod.rs | 37 +++++++++++++++++++++++++++++-------- 1 file changed, 29 insertions(+), 8 deletions(-) (limited to 'src/protected_mode/mod.rs') diff --git a/src/protected_mode/mod.rs b/src/protected_mode/mod.rs index f4e355f..200e12f 100644 --- a/src/protected_mode/mod.rs +++ b/src/protected_mode/mod.rs @@ -4936,6 +4936,7 @@ enum OperandCase { AX_Ib, Ib_AL, Ib_AX, + Gv_Ew_LAR, Gv_Ew_LSL, // Gdq_Ev, Gd_Ev, @@ -5266,6 +5267,7 @@ enum OperandCode { Zv_Iv_R7 = OperandCodeBuilder::new().op0_is_rrr_and_Z_operand(ZOperandCategory::Zv_Iv_R, 7).bits(), Gv_Eb = OperandCodeBuilder::new().read_E().operand_case(OperandCase::Gv_Eb).bits(), Gv_Ew = OperandCodeBuilder::new().read_E().operand_case(OperandCase::Gv_Ew).bits(), + Gv_Ew_LAR = OperandCodeBuilder::new().read_E().operand_case(OperandCase::Gv_Ew_LAR).bits(), Gv_Ew_LSL = OperandCodeBuilder::new().read_E().operand_case(OperandCase::Gv_Ew_LSL).bits(), // Gdq_Ed = OperandCodeBuilder::new().read_E().operand_case(OperandCase::Gdq_Ed).bits(), Gd_Ed = OperandCodeBuilder::new().read_E().operand_case(OperandCase::Gd_Ed).bits(), @@ -7940,12 +7942,31 @@ fn read_operands< instruction.regs[1].bank = RegisterBank::MM; instruction.regs[1].num &= 0b111; }, - OperandCase::Gv_Ew_LSL => { + OperandCase::Gv_Ew_LAR => { instruction.operands[1] = mem_oper; - // lsl is weird. the full register width is written, but only the low 16 bits are used. - if instruction.operands[1] == OperandSpec::RegMMM { - instruction.regs[1].bank = RegisterBank::D; + // lar is weird. a segment selector is taken from the source register, which means + // either we read the low 16-bits of a register or read 16 bits from a memory operand. + // for whatever reason, the intel manual writes a source register as a dword/qword for + // larger modes even though the upper 16 bits would be ignored. + // + // so the registers are correct by the time we're here, we might just need to override + // mem size as well. + if instruction.operands[1] != OperandSpec::RegMMM { + instruction.mem_size = 2; + } + instruction.regs[0].bank = if instruction.prefixes.operand_size() { + RegisterBank::W } else { + RegisterBank::D + }; + }, + OperandCase::Gv_Ew_LSL => { + instruction.operands[1] = mem_oper; + // lsl is weird. a segment selector is taken from the source register, which means + // either we read the low 16-bits of a register or read 16 bits from a memory operand. + // for whatever reason, the intel manual writes a source register as a dword for larger + // modes even though the upper 16 bits would be ignored. + if instruction.operands[1] != OperandSpec::RegMMM { instruction.mem_size = 2; } instruction.regs[0].bank = if instruction.prefixes.operand_size() { @@ -10743,7 +10764,7 @@ fn read_modrm::Address,