From 07e1e6b6e272740dd77810e64704119d06500f29 Mon Sep 17 00:00:00 2001
From: Daniil Rose <daniil.rose@member.fsf.org>
Date: Thu, 30 Dec 2021 22:06:26 -0500
Subject: [PATCH] Add basic hex dump auto disassembler

---
 main.c | 94 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 91 insertions(+), 3 deletions(-)

diff --git a/main.c b/main.c
index f26b97c..69300e3 100644
--- a/main.c
+++ b/main.c
@@ -1,6 +1,94 @@
 #include <stdio.h>
 
-int main() {
-    printf("Hello, World!\n");
-    return 0;
+int disassemble_8080_op(unsigned char *codebuffer, int pc);
+
+int main (int argc, char**argv) {
+  FILE *f= fopen(argv[1], "rb");
+
+  if (f==NULL) {
+    printf("error: Couldn't open %s\n", argv[1]);
+    exit(1);
+  }
+
+  fseek(f, 0L, SEEK_END);
+  int fsize = ftell(f);
+  fseek(f, 0L, SEEK_SET);
+
+  unsigned char *buffer=malloc(fsize);
+
+  fread(buffer, fsize, 1, f);
+  fclose(f);
+
+  int pc = 0;
+
+  while (pc < fsize) {
+    pc += disassemble_8080_op(buffer, pc);
+  }
+
+  return 0;
+}
+
+/*
+ * *codebuffer is a valid pointer to 8080 assembly code
+ * pc is the current offset into the code
+ *
+ * returns the number of bytes of the op
+ */
+
+/*
+ * TODO: Finish writing out 8080 opcodes
+ */
+
+int disassemble_8080_op(unsigned char *codebuffer, int pc) {
+  unsigned char *code = &codebuffer[pc];
+  int opbytes = 1;
+
+  printf ("%04x ", pc);
+
+  switch (*code) {
+    case 0x00:
+      printf("NOP");
+      break;
+    case 0x01:
+      printf("LXI    B,#$%02x%02x", code[2], code[1]);
+      opbytes=3;
+      break;
+    case 0x02:
+      printf("STAX   B");
+      break;
+    case 0x03:
+      printf("INX    B");
+      break;
+    case 0x04:
+      printf("INR    B");
+      break;
+    case 0x05:
+      printf("DCR    B");
+      break;
+    case 0x06:
+      printf("MVI    B,#$%02x", code[1]);
+      opbytes=2;
+      break;
+    case 0x07:
+      printf("RLC");
+      break;
+    case 0x08:
+      printf("NOP");
+      break;
+      /* ........ */
+    case 0x3e:
+      printf("MVI    A,#0x%02x", code[1]);
+      opbytes = 2;
+      break;
+      /* ........ */
+    case 0xc3:
+      printf("JMP    $%02x%02x", code[2], code[1]);
+      opbytes = 3;
+      break;
+      /* ........ */
+  }
+
+  printf("\n");
+
+  return opbytes;
 }
-- 
2.45.2