From 78c011354565692c9b154637f2ab1d841de02764 Mon Sep 17 00:00:00 2001
From: Vince Weaver <vince@deater.net>
Date: Wed, 16 Jan 2013 21:49:25 -0500
Subject: [PATCH] snes: checksum working

Finally got the checksum working.  I had the checksum/complement
fields reversed somehow.
---
 tb_snes/Makefile              |  9 ++++++++-
 tb_snes/checksum.inc          |  2 ++
 tb_snes/tb1_snes.s            |  6 ++----
 tb_snes/tools/snes_checksum.c | 19 ++++++++++++++-----
 4 files changed, 26 insertions(+), 10 deletions(-)
 create mode 100644 tb_snes/checksum.inc

diff --git a/tb_snes/Makefile b/tb_snes/Makefile
index 99224d2..a6e4c8e 100644
--- a/tb_snes/Makefile
+++ b/tb_snes/Makefile
@@ -2,7 +2,8 @@ AS=cl65
 LD=ld65
 
 
-all:	tb1_snes.sfc
+all:	checksum.inc
+
 
 tb1_snes.sfc:	tb1_snes.o snes-hirom.cfg
 	$(LD) -o tb1_snes.sfc --config snes-hirom.cfg --obj tb1_snes.o
@@ -14,6 +15,12 @@ tb1_snes.o:	tb1_snes.s snes_init.s \
 tb1_title.tiles:	graphics/tb1_title.pcx ./tools/pcx_to_tiles_8bpp
 	./tools/pcx_to_tiles_8bpp < graphics/tb1_title.pcx > tb1_title.tiles
 
+checksum.inc:	./tools/snes_checksum tb1_snes.sfc
+	./tools/snes_checksum < tb1_snes.sfc > checksum.inc
+
+tools/snes_checksum:	
+	cd tools && make
+
 tools/pcx_to_tiles_8bpp:	
 	cd tools && make
 
diff --git a/tb_snes/checksum.inc b/tb_snes/checksum.inc
new file mode 100644
index 0000000..7ff8250
--- /dev/null
+++ b/tb_snes/checksum.inc
@@ -0,0 +1,2 @@
+	.word	$c807		; Complement of checksum
+	.word	$37f8		; Unsigned 16-bit sum of ROM
diff --git a/tb_snes/tb1_snes.s b/tb_snes/tb1_snes.s
index 6bf9195..3ece6c2 100644
--- a/tb_snes/tb1_snes.s
+++ b/tb_snes/tb1_snes.s
@@ -293,10 +293,8 @@ output:
         .byte   $01			; Country Code (1=NTSC,2=PAL)
 	.byte	$00			; License Code (0=unassigned)
         .byte   $00			; Version
-        .word   $37f8		; Unsigned 16-bit sum of ROM
-        .word	$c807		; Complement of checksum
-
-	.word   $0,$0		; unknown?
+.include "checksum.inc"
+	.word   $0,$0			; unknown?
 
 	; Interrupt Vectors!
 
diff --git a/tb_snes/tools/snes_checksum.c b/tb_snes/tools/snes_checksum.c
index af58b8f..55e2570 100644
--- a/tb_snes/tools/snes_checksum.c
+++ b/tb_snes/tools/snes_checksum.c
@@ -2,26 +2,35 @@
 
 int main(int argc, char **argv) {
 
-   int byte;
+   int byte,offset=0;
    unsigned int total=0;
    unsigned short checksum;
+   int debug=0;
    
    while(1) {
       byte=fgetc(stdin);
       if (byte<0) break;
 	
+      if (debug) {
+         if (offset==0xffdc) printf("%x\n",byte);
+         if (offset==0xffdd) printf("%x\n",byte);
+         if (offset==0xffde) printf("%x\n",byte);
+         if (offset==0xffdf) printf("%x\n",byte);      
+      }
+      
       total+=byte;
+      offset++;
 
    }
       
    checksum=total&0xffff;
    
-   printf("Checksum: %hx\n",checksum);
-   printf("Complement: %hx\n",~checksum);
-   
+   printf("\t.word\t$%hx\t\t; Complement of checksum\n",~checksum);
+   printf("\t.word\t$%hx\t\t; Unsigned 16-bit sum of ROM\n",checksum);
+     
    return 0;
    
    
 }
 
-   
\ No newline at end of file
+