From 5b0d2d754fc84bc32807b939c92d43be700ef4d5 Mon Sep 17 00:00:00 2001 From: Thomas Harte Date: Thu, 26 Oct 2023 23:27:56 -0400 Subject: [PATCH] Update comments. --- InstructionSets/x86/Instruction.hpp | 17 ++++------------- 1 file changed, 4 insertions(+), 13 deletions(-) diff --git a/InstructionSets/x86/Instruction.hpp b/InstructionSets/x86/Instruction.hpp index 71292b506..ba6e28dca 100644 --- a/InstructionSets/x86/Instruction.hpp +++ b/InstructionSets/x86/Instruction.hpp @@ -693,13 +693,11 @@ template class Instruction { // Packing and encoding of fields is admittedly somewhat convoluted; what this // achieves is that instructions will be sized: // - // four bytes + up to three extension words - // (two bytes for 16-bit instructions, four for 32) + // four bytes + up to two extension words + // (extension words being two bytes for 16-bit instructions, four for 32) // - // Two of the extension words are used to retain an operand and displacement - // if the instruction has those. The other can store sizes greater than 15 - // bytes (for earlier processors), plus any repetition, segment override or - // repetition prefixes. + // The extension words are used to retain an operand and displacement + // if the instruction has those. // b7: address size; // b6: has displacement; @@ -739,13 +737,6 @@ template class Instruction { return offsetof(Instruction, extensions) + (has_displacement() + has_operand()) * sizeof(ImmediateT); - - // To consider in the future: the length extension is always the last one, - // and uses only 8 bits of content within 32-bit instructions, so it'd be - // possible further to trim the packing size on little endian machines. - // - // ... but is that a speed improvement? How much space does it save, and - // is it enough to undo the costs of unaligned data? } private: