X-Git-Url: https://git.zerfleddert.de/cgi-bin/gitweb.cgi/rsbs2/blobdiff_plain/2363a0d6a8cf44f7288e0795ff29e081ecf3a08f..e515e1d73160e0564fe39295664e4798072a6bc4:/rsb-crc.c diff --git a/rsb-crc.c b/rsb-crc.c index 8c8fbbe..6a2bf99 100644 --- a/rsb-crc.c +++ b/rsb-crc.c @@ -2,41 +2,6 @@ #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 - * 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 - */ - 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; @@ -66,55 +31,6 @@ 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_out) { unsigned int r4_len; unsigned int file_crc;