From 9a136e354d63c32c2471f473b1fed0cf3db9abde Mon Sep 17 00:00:00 2001 From: Itamar Date: Sat, 10 Dec 2022 15:05:07 +0200 Subject: [PATCH] LibX86: Use AddressSize::32 in Long mode As the existing near-by comment says, the default size of displacements & immediates is 32 bits even in Long mode. This makes `disasm` work on our binaries in x86-64 builds. --- Userland/Libraries/LibX86/Instruction.h | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/Userland/Libraries/LibX86/Instruction.h b/Userland/Libraries/LibX86/Instruction.h index 10ea32adda..238e070285 100644 --- a/Userland/Libraries/LibX86/Instruction.h +++ b/Userland/Libraries/LibX86/Instruction.h @@ -1007,11 +1007,12 @@ ALWAYS_INLINE Instruction::Instruction(InstructionStreamType& stream, OperandSiz , m_address_size(address_size) { VERIFY(operand_size != OperandSize::Size64); - // Use address_size as the hint to switch into long mode, m_address_size refers to the default - // size of displacements/immediates, which is 32 even in long mode, with the exception of moffset (see below). + // Use address_size as the hint to switch into long mode. + // m_address_size refers to the default size of displacements/immediates, which is 32 even in long mode (2.2.1.3 Displacement, 2.2.1.5 Immediates), + // with the exception of moffset (see below). if (address_size == AddressSize::Size64) { m_operand_size = OperandSize::Size32; - m_address_size = AddressSize::Size64; + m_address_size = AddressSize::Size32; m_mode = ProcessorMode::Long; } u8 prefix_bytes = 0; @@ -1124,7 +1125,7 @@ ALWAYS_INLINE Instruction::Instruction(InstructionStreamType& stream, OperandSiz return; } - // 2.2.1.3 Direct Memory-Offset MOVs + // 2.2.1.4 Direct Memory-Offset MOVs auto effective_address_size = m_address_size; if (m_mode == ProcessorMode::Long) { switch (m_descriptor->format) {