From 1ac8ab06e9aad3b6d22685255459d71cb49e1f28 Mon Sep 17 00:00:00 2001
From: Roland Reichwein <mail@reichwein.it>
Date: Mon, 9 Nov 2020 09:50:58 +0100
Subject: First program: Can add 2 integers and return result via exit code

---
 asm/intel64/add.cpp | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

(limited to 'asm/intel64/add.cpp')

diff --git a/asm/intel64/add.cpp b/asm/intel64/add.cpp
index 106ffec..4438895 100644
--- a/asm/intel64/add.cpp
+++ b/asm/intel64/add.cpp
@@ -12,8 +12,12 @@ Op_add::Op_add(Asm::Args& args)
  if (args[0].type() == typeid(Asm::Args::Register32) &&
      std::any_cast<Asm::Args::Register32>(args[0]).name() == "eax" &&
      args[1].type() == typeid(Asm::Args::Immediate32))
- { // add eax, imm32
+ { // add eax, imm32 (before "add reg32, imm32"! It's shorter.)
   machine_code = std::vector<uint8_t>{ 0x05 } + std::any_cast<Asm::Args::Immediate32>(args[1]).getCode();
+ } else if (args[0].type() == typeid(Asm::Args::Register32) &&
+     args[1].type() == typeid(Asm::Args::Immediate32))
+ { // add reg32, imm32
+  machine_code = std::vector<uint8_t>{ 0x81 } + ModRM("/0", std::any_cast<Asm::Args::Register32>(args[0]).name()) + std::any_cast<Asm::Args::Immediate32>(args[1]).getCode();
  } else if (args[0].type() == typeid(Asm::Args::Register64) &&
             std::any_cast<Asm::Args::Register64>(args[0]).name() == "rax"  &&
             args[1].type() == typeid(Asm::Args::Immediate32))
-- 
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