RegMemMode enum, Instruction struct with 'mov' encodings, plus a map, read bytes

decoder8086.odin

@@ -15,6 +15,13 @@ Register :: struct {
     code: u8,
 }
 
+RegMemMode :: enum {
+    Memory00 = 0b00,
+    Memory08 = 0b01,
+    Memory16 = 0b10,
+    Register = 0b11,
+};
+
 registers := [8]Register {
     {fullname = "ax", bytename = "al", code = 0b000},
     {fullname = "cx", bytename = "cl", code = 0b001},
@@ -26,30 +33,52 @@ registers := [8]Register {
     {fullname = "di", bytename = "bh", code = 0b111},
 }
 
+Instruction :: struct {
+    mask: u8,
+    encoding: u8,
+    name: string,
+    desc: string,
+}
+
+instructions := [?]Instruction {
+    { mask = 0b11111100, encoding = 0b10001000, name = "mov", desc = "Register/memory to/from register" },
+    { mask = 0b11111110, encoding = 0b11000110, name = "mov", desc = "Immediate to register/memory" },
+    { mask = 0b11110000, encoding = 0b10110000, name = "mov", desc = "Immediate to register" },
+    { mask = 0b11111110, encoding = 0b10100000, name = "mov", desc = "Memory to accumulator" },
+    { mask = 0b11111110, encoding = 0b10100010, name = "mov", desc = "Accumulator to memory" },
+    { mask = 0b11111111, encoding = 0b10001110, name = "mov", desc = "Register/memory to segment register" },
+    { mask = 0b11111111, encoding = 0b10001100, name = "mov", desc = "Segment register to register/memory" },
+}
+
+inst_map := make(map[u8]Instruction)
+
 main :: proc() {
     ax := registers[0]
     ax.value.full = 52428
-    f,err := os.open(len(os.args) > 1 ? os.args[1] : "./asm_files/01-01-38.bin")
+    f,err := os.open(len(os.args) > 1 ? os.args[1] : "./asm_files/01-02-39.bin")
     if err != os.ERROR_NONE {
         os.exit(1)
     }
     defer os.close(f)
 
-    data := make([]u8, 256)
+    data := make([]u8, 512)
     bytes_read, err2 := os.read(f, data)
     if err2 != nil {
         // ...
         os.exit(1)
     }
-    // mov cx, bx                      ; mov 001, 011
-    // mov dx, bx
+
+    for inst in instructions {
+        inst_map[inst.encoding] = inst
+    }
 
     read_next := false
     src_dst := true
     is_word := false
     prev :u8 = 0
     fmt.println("bits 16\n")
-    for b in data {
+    for i in 0..<bytes_read {
+        b := data[i]
         if read_next {
             mod := (b & 0b11000000) >> 6
             reg := (b & 0b00111000) >> 3