From 7c2ca230ffb88ae7d7ff9a68e5ad5e7ce17f4a5b Mon Sep 17 00:00:00 2001
From: Jared Burce <jaredr@gmail.com>
Date: Wed, 7 Apr 2021 02:06:03 -0700
Subject: [PATCH] emu: XCHG op

---
 src/emu/i8088.rs      | 9 +++++++++
 src/emu/operations.rs | 6 ++++++
 2 files changed, 15 insertions(+)

diff --git a/src/emu/i8088.rs b/src/emu/i8088.rs
index 6370fe0..89a8c8d 100644
--- a/src/emu/i8088.rs
+++ b/src/emu/i8088.rs
@@ -473,6 +473,8 @@ impl i8088 {
           0x80: { 0x38 => cmp[flags, modrm8, d8] / "4/23+", },
           0x81: { 0x38 => cmp[flags, modrm16, d16] / "4/23+", },
           0x83: { 0x38 => cmp[flags, modrm16, d8_as_d16] / "4/23+", },
+          0x86 _ => xchg[r8, modrm8] / "4/25+",   // XCHG r8, r/m8
+          0x87 _ => xchg[r16, modrm16] / "4/25+", // XCHG r16, r/m16
           0x88 _ => mov[modrm8, r8] / "2/13+",    // MOV r/m8, r8
           0x89 _ => mov[modrm16, r16] / "2/13+",  // MOV r/m16, r16
           0x8A _ => mov[r8, modrm8] / "2/12+",    // MOV r8, r/m8
@@ -488,6 +490,13 @@ impl i8088 {
                   0x18 => mov[reg=ds, modrm16] / "2/12+", }, // MOV ds, r/m16
           0x8F: { 0x00 => pop_modrm[regval=ss, reg=sp, modrm16, convert, bus] / "12/25+" },  // POP r/m16
           0x90 => nop[] / 3,
+          0x91 => xchg[reg=a, reg=c] / 3,   // XCHG ax, cx
+          0x92 => xchg[reg=a, reg=d] / 3,   // XCHG ax, dx
+          0x93 => xchg[reg=a, reg=b] / 3,   // XCHG ax, bx
+          0x94 => xchg[reg=a, reg=sp] / 3,  // XCHG ax, sp
+          0x95 => xchg[reg=a, reg=bp] / 3,  // XCHG ax, bp
+          0x96 => xchg[reg=a, reg=si] / 3,  // XCHG ax, si
+          0x97 => xchg[reg=a, reg=di] / 3,  // XCHG ax, di
           0x9C => push[bus, regval=ss, reg=sp, flags] / 14,  // PUSHF
           0x9D => pop[bus, regval=ss, reg=sp, flags] / 12,   // POPF
           // 0x9E SAHF not implemented
diff --git a/src/emu/operations.rs b/src/emu/operations.rs
index 124d968..d67b337 100644
--- a/src/emu/operations.rs
+++ b/src/emu/operations.rs
@@ -618,3 +618,9 @@ where RVal: RValue<T>,
     dst.write(val.read());
   });
 }
+
+pub fn xchg<T, Dst: LValue<T>, Src: LValue<T>>(mut dst: Dst, mut src: Src) {
+  let tmp = src.read();
+  src.write(dst.read());
+  dst.write(tmp);
+}