X-Git-Url: http://git.zerfleddert.de/cgi-bin/gitweb.cgi/rsbs2/blobdiff_plain/972ac24b5466e95d78f4af724c2f4e197f340eb5..e726b380eaf48b6af8b06fe28383a183f35ceace:/rsb-crc.c

diff --git a/rsb-crc.c b/rsb-crc.c
index 84b7fa2..6a2bf99 100644
--- a/rsb-crc.c
+++ b/rsb-crc.c
@@ -1,64 +1,54 @@
-#define POLY 0x04c11db7
+#include <stdio.h>
 
-/* Theory of operation:
- * (arm-elf-objdump -b binary -m arm -M reg-names-raw -D RSB_S2_SINGLE.bin)
- *
- * 440: push  {r4, r5, r6, r7, r8, r9, r10, r11, r14}
- * 444: mov   r11, r0
- * 448: mov   r10, r1
- * 44c: mov   r14, r2
- * 450: mov   r6, #0	; 0x0
- * 454: b     0x4a0
- * 458: add   r3, r6, r10
- * 45c: ldrb  r3, [r3]
- * 460: lsl   r3, r3, #24
- * 464: eor   r11, r11, r3
- * 468: mov   r5, #8	; 0x8
- * 46c: and   r3, r11, #-2147483648	; 0x80000000
- * 470: cmp   r3, #0	; 0x0
- * 474: beq   0x48c
- * 478: lsl   r3, r11, #1
- * 47c: ldr   r12, [pc, #64]	; 0x4c4
- * 480: eor   r0, r3, r12
- * 484: mov   r11, r0
- * 488: b     0x490
- * 48c: lsl   r11, r11, #1
- * 490: sub   r5, r5, #1	; 0x1
- * 494: cmp   r5, #0		; 0x0
- * 498: bne   0x46c
- * 49c: add   r6, r6, #1	; 0x1
- * 4a0: cmp   r6, r14
- * 4a4: blt   0x458
- * 4a8: mov   r0, r11
- * 4ac: pop   {r4, r5, r6, r7, r8, r9, r10, r11, r15}
- * 4c4: DATA: 0x04c11db7
- */
+#define POLY 0x04c11db7
 
-unsigned int rsb_crc(unsigned int r11, unsigned char *r10, unsigned int r14) {
-	unsigned int r6 = 0;
-	unsigned int r3;
-	int r5;
+unsigned int rsb_crc(unsigned int r11_crc, unsigned char *r10_buf, unsigned int r14_len) {
+	unsigned int r6_pos = 0;
+	unsigned int r3_data;
+	int r5_bit;
 
-	while (r6 < r14) {
-		r3 = (*(r6+r10)) << 24;
-		r11 = r11 ^ r3;
+	while (r6_pos < r14_len) {
+		r3_data = (*(r6_pos+r10_buf)) << 24;
+		r11_crc = r11_crc ^ r3_data;
 
-		r5 = 8;
+		r5_bit = 8;
 		
 		do {
-			r3 = r11 & 0x80000000;
+			r3_data = r11_crc & 0x80000000;
 
-			if (r3 != 0) {
-				r3 = r11 << 1;
-				r11 = r3 ^ POLY;
+			if (r3_data != 0) {
+				r3_data = r11_crc << 1;
+				r11_crc = r3_data ^ POLY;
 			} else {
-				r11 = r11 << 1;
+				r11_crc = r11_crc << 1;
 			}
-			r5--;
-		} while (r5);
+			r5_bit--;
+		} while (r5_bit);
 
-		r6++;
+		r6_pos++;
 	}
 
-	return r11;
+	return r11_crc;
+}
+
+unsigned int rsb_crc2(unsigned char *r0_buf, unsigned int r1_buflen, unsigned int r2_magic, unsigned int *crc_out) {
+	unsigned int r4_len;
+	unsigned int file_crc;
+
+	r4_len = *(unsigned int*)(r0_buf + 0x20);
+
+	if (*((unsigned int*)(r0_buf + 0x24)) != r2_magic)
+		return 2; /* MAGIC does not match */
+	
+	if (r1_buflen < r4_len)
+		return 3; /* image to small */
+	
+	*crc_out = ~rsb_crc(~0x0, r0_buf, r4_len);
+
+	file_crc = *((unsigned int*)(r0_buf + r4_len));
+
+	if (file_crc != *crc_out)
+		return 4;
+
+	return 0;
 }