implement second agilent crc algorithm

diff --git a/Makefile b/Makefile
index 6122eeaa93aa867cbc3fecec714a9c9e44cd33b0..6b43a5f33709ac03e187f5421a439bc663cc0847 100644 (file)
--- a/Makefile
+++ b/Makefile
@@ -1,4 +1,4 @@
-CFLAGS=-Wall
+CFLAGS=-Wall -O3
 
 all: firmware 
 

diff --git a/firmware.c b/firmware.c
index f8584c163caa3ef4aa9aec3250dccc8e37d6cfe8..67f1f0a894ceba5912da60c73617f9bea9be2505 100644 (file)
--- a/firmware.c
+++ b/firmware.c
@@ -8,38 +8,6 @@
 #include <strings.h>
 #include "rsb-crc.h"
 
-struct fw_header {
-       unsigned int unknown[8];
-       unsigned int len;
-       char ident[4];
-       unsigned int offset;
-       char desc[128];
-};
-
-void parse_fw(unsigned char *fw, unsigned int off) {
-       struct fw_header *header = (struct fw_header*)(fw + off);
-       static unsigned int last_off;
-       int i;
-
-       printf("Address in file: 0x%08x, Difference to last: %u\n", off, off-last_off);
-       printf("Unknown: ");
-       for (i = 0; i < 8; i++)
-               printf("0x%08x ", header->unknown[i]);
-
-       printf("\n");
-
-       printf("Length: %u, possible next entry at: 0x%08x\n", header->len, off + header->len + 22);
-
-       printf("Identifier: %.4s\n", header->ident);
-
-       printf("Offset: 0x%08x\n", header->offset);
-
-       printf("Descriptiom: %s\n", header->desc);
-
-       printf("\n");
-       last_off = off;
-}
-
 int main(int argc, char **argv)
 {
        struct stat statbuf;
@@ -47,7 +15,7 @@ int main(int argc, char **argv)
        int fd;
        int remaining;
        int ret;
-       unsigned int crc;
+       unsigned int crc, oldcrc;
 
        if (argc != 2) {
                fprintf(stderr,"Syntax: %s firmware.bin\n", argv[0]);
@@ -81,15 +49,10 @@ int main(int argc, char **argv)
                remaining -= ret;
        }
 
-#if 0
-       parse_fw(fw, 0x0);
-       parse_fw(fw, 0x555c0);
-       parse_fw(fw, 0x5940e);
-#endif
-
-       crc = rsb_crc(0, fw, statbuf.st_size-4);
+       ret = rsb_crc2(fw, statbuf.st_size, 0x55335053, &crc);
+       oldcrc = (unsigned int)*((unsigned int*)(fw + statbuf.st_size - 4));
 
-       printf("Length: %ld, Checksum: 0x%08x\n", statbuf.st_size-4, crc);
+       printf("Checksum: 0x%08x, should be: 0x%08x\n", crc, oldcrc);
 
        exit(0);
 }

diff --git a/rsb-crc.c b/rsb-crc.c
index fa40c498099e3b3838e8e325f00b844940287bc1..3fe5cbc2ed4ca53473eaee16e3e5698bee110c6b 100644 (file)
--- a/rsb-crc.c
+++ b/rsb-crc.c
@@ -1,7 +1,10 @@
+#include <stdio.h>
+
 #define POLY 0x04c11db7
 
 /* Theory of operation:
  * (arm-elf-objdump -b binary -m arm -M reg-names-raw -D RSB_S2_SINGLE.bin)
+ * Addresses: 0x4c4, 0x55ae0, 0x59734
  *
  * 440: push  {r4, r5, r6, r7, r8, r9, r10, r11, r14}
  * 444: mov   r11, r0
@@ -62,3 +65,129 @@ unsigned int rsb_crc(unsigned int r11_crc, unsigned char *r10_buf, unsigned int
 
        return r11_crc;
 }
+
+/* Second broken algorithm:
+ *
+ * 55a30: push    {r3, r4, r5, r6, r7, r8, r9, r14}
+ * 55a34: bl      0x55a3c
+ * 55a38: pop     {r3, r4, r5, r6, r7, r8, r9, r15}
+ * 55a3c: mov     r8, #1  ; 0x1
+ * 55a40: mov     r3, #-1073741824        ; 0xc0000000
+ * 55a44: cmp     r0, r3
+ * 55a48: ble     0x55ad8
+ * 55a4c: mov     r3, #32 ; 0x20
+ * 55a50: ldr     r4, [r3, r0]!
+ * 55a54: mov     r8, #2  ; 0x2
+ * 55a58: ldr     r5, [r3, #4]
+ * 55a5c: cmp     r5, r2
+ * 55a60: bne     0x55ad8
+ * 55a64: mov     r8, #3  ; 0x3
+ * 55a68: cmp     r1, r4
+ * 55a6c: movscs  r5, #0  ; 0x0
+ * 55a70: movscc  r5, #1  ; 0x1
+ * 55a74: bne     0x55ad8
+ * 55a78: mov     r8, #4  ; 0x4
+ * 55a7c: mov     r3, r0
+ * 55a80: add     r4, r0, r4
+ * 55a84: mvn     r5, #0  ; 0x0
+ * 55a88: ldr     r7, [pc, #80]   ; 0x55ae0
+ * 55a8c: cmp     r3, r4
+ * 55a90: bcs     0x55ac8
+ * 55a94: bic     r9, r3, #3      ; 0x3
+ * 55a98: ldr     r6, [r9]
+ * 55a9c: and     r9, r3, #3      ; 0x3
+ * 55aa0: lsl     r9, r9, #3
+ * 55aa4: lsr     r6, r6, r9
+ * 55aa8: eor     r5, r5, r6, lsl #24
+ * 55aac: mov     r6, #8  ; 0x8
+ * 55ab0: lsls    r5, r5, #1
+ * 55ab4: eorcs   r5, r5, r7
+ * 55ab8: subs    r6, r6, #1      ; 0x1
+ * 55abc: bne     0x55ab0
+ * 55ac0: add     r3, r3, #1      ; 0x1
+ * 55ac4: b       0x55a8c
+ * 55ac8: mvn     r5, r5
+ * 55acc: ldr     r3, [r4]
+ * 55ad0: subs    r3, r3, r5
+ * 55ad4: moveq   r8, #0  ; 0x0
+ * 55ad8: mov     r0, r8
+ * 55adc: mov     r15, r14
+ * 55ae0: DATA:   0x04c11db7
+ */
+
+unsigned int rsb_crc2(unsigned char *r0_buf, unsigned int r1_buflen, unsigned int r2_magic, unsigned int *crc) {
+       int r8_ret = 1;
+       unsigned int r3 = 0xc0000000;
+       unsigned int r4_len;
+       unsigned int r5;
+       unsigned int r6;
+       unsigned int r7_poly;
+       unsigned int r9;
+       unsigned int carry;
+
+#if 0
+       if (r0_buf <= r3)
+               return r8_ret;
+#endif
+
+       r3 = ((unsigned int)r0_buf) + 0x20;
+       r4_len = *((unsigned int*)r3);
+       printf("CRC: length: %d\n", r4_len);
+
+       r8_ret = 2;
+
+       r3 += 4;
+       r5 = *((unsigned int*)r3);
+
+       if (r5 != r2_magic)
+               return r8_ret;
+       
+       r8_ret = 3;
+
+       if (r1_buflen >= r4_len) {
+               r5 = 0;
+       } else {
+               r5 = 1;
+       }
+
+       if (r5 != 0)
+               return r8_ret;
+       
+       r8_ret = 4;
+
+       r3 = (unsigned int)r0_buf;
+       r4_len += r3;
+       
+       r5 = ~0x0;
+
+       r7_poly = POLY;
+
+       while (r3 < r4_len) {
+               r9 = r3 & (~0x3);
+               r6 = *((unsigned int*)r9);
+               r9 = r3 & 0x3;
+               r9 = r9 << 0x3;
+               r6 = r6 >> r9;
+               r5 = r5 ^ (r6 << 24);
+               r6 = 0x8;
+
+               do {
+                       carry = r5 & 0x80000000;
+                       r5 = r5 << 1;
+                       if (carry)
+                               r5 = r5 ^ r7_poly;
+                       r6--;
+               } while(r6);
+               r3++;
+       }
+
+       r5 = ~r5;
+       *crc = r5;
+
+       r3 = *((unsigned int*)r4_len);
+
+       if (r3 == r5)
+               r8_ret = 0;
+
+       return r8_ret;
+}

diff --git a/rsb-crc.h b/rsb-crc.h
index 94d327dc51d68fe6bb10084d43cc470d0fe96cee..c59ccde0b791828f99069ed6877995c54fe5569d 100644 (file)
--- a/rsb-crc.h
+++ b/rsb-crc.h
@@ -1 +1,2 @@
-unsigned int rsb_crc(unsigned int r11, unsigned char *r10, unsigned int r14);
+unsigned int rsb_crc(unsigned int r11_crc, unsigned char *r10_buf, unsigned int r14_len);
+unsigned int rsb_crc2(unsigned char *r0_buf, unsigned int r1_buflen, unsigned int r2_magic, unsigned int *crc);