From 0e4aebff135f123aa3a403524fb662f2e1ab68c0 Mon Sep 17 00:00:00 2001
From: Joseph Ferano <joseph@ferano.io>
Date: Tue, 21 Jan 2025 14:20:41 +0700
Subject: [PATCH] Odin port

---
 decoder8086.odin | 62 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 62 insertions(+)
 create mode 100644 decoder8086.odin

diff --git a/decoder8086.odin b/decoder8086.odin
new file mode 100644
index 0000000..e4d3ba5
--- /dev/null
+++ b/decoder8086.odin
@@ -0,0 +1,62 @@
+package decoder_8086
+
+import "core:os"
+import "core:fmt"
+
+Register :: struct {
+    fullname: string,
+    bytename: string,
+    value: struct #raw_union {
+        using _: struct {
+            low, high: byte,
+        },
+        full: u16,
+    },
+    code: u8,
+}
+
+registers := [8]Register {
+    {fullname = "ax", bytename = "al", code = 0b000},
+    {fullname = "cx", bytename = "cl", code = 0b001},
+    {fullname = "dx", bytename = "dl", code = 0b010},
+    {fullname = "bx", bytename = "bl", code = 0b011},
+    {fullname = "sp", bytename = "ah", code = 0b100},
+    {fullname = "bp", bytename = "ch", code = 0b101},
+    {fullname = "si", bytename = "dh", code = 0b110},
+    {fullname = "di", bytename = "bh", code = 0b111},
+}
+
+main :: proc() {
+    ax := registers[0]
+    ax.value.full = 52428
+    f,err := os.open("./asm_files/01-01-38.bin")
+    if err != os.ERROR_NONE {
+        os.exit(1)
+    }
+    defer os.close(f)
+
+    data := make([]u8, 256)
+    bytes_read, err2 := os.read(f, data)
+    if err2 != nil {
+        // ...
+        os.exit(1)
+    }
+    // mov cx, bx                      ; mov 001, 011
+    // mov dx, bx
+
+    read_next := false
+    for b in data {
+        if read_next {
+            mod := (b & 0b11000000) >> 6
+            reg := (b & 0b00111000) >> 3
+            rm  := b & 0b00000111
+            fmt.printfln("mov %s, %s", registers[rm].fullname, registers[reg].fullname)
+            read_next = false
+            continue
+        }
+        if b == 0b10001001 {
+            read_next = true
+            continue
+        }
+    }
+}