# # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # Copyright (c) Freescale Semiconductor, Inc 2013. # # FILE NAME : mmcau_des_functions.s # VERSION : $Id: $ # TYPE : Source Cortex-M0+ assembly library code # DEPARTMENT : MCG R&D Cores and Platforms # AUTHOR : Anthony (Teejay) Ciancio # AUTHOR EMAIL : teejay.ciancio@freescale.com # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # VERSION DATE AUTHOR DESCRIPTION # ******* **** ****** *********** # 1.0 2013-11 Ciancio initial release, using the ARMv6-M ISA # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # .include "cau2_defines.hdr" .syntax unified .equ MMCAU_PPB_DIRECT, 0xf0005000 .equ MMCAU_PPB_INDIRECT, 0xf0005800 .equ MMCAU_1_CMD, 0x80000000 .equ MMCAU_2_CMDS, 0x80100000 .equ MMCAU_3_CMDS, 0x80100200 # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # MMCAU_DES_CHK_PARITY # Check key parity # # ARGUMENTS # *key pointer to 64-bit DES key with parity bits # return 0 no error # -1 parity error # # CALLING CONVENTION # int mmcau_des_chk_parity (const unsigned char *key) # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # REGISTER | ALLOCATION (at the start of mmcau_des_chk_parity) # -----------+------------------------------------------------------------ # r0 | *key (arg0) # | # > r0 | irrelevant # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # .global _mmcau_des_chk_parity .global mmcau_des_chk_parity .type mmcau_des_chk_parity, %function .align 4 _mmcau_des_chk_parity: mmcau_des_chk_parity: # load the 64-bit key into the CAU's CA0/CA1 regs ldr r3, =MMCAU_PPB_INDIRECT+((LDR+CA0)<<2) ldmia r0!, {r1-r2} @ load key str r1, [r3, #0<<2] @ store lower half in CA0 str r2, [r3, #1<<2] @ store upper half in CA1 ldr r1, =MMCAU_PPB_DIRECT ldr r2, =MMCAU_1_CMD+((DESK+CP)<<22) str r2, [r1] @ perform the key schedule # CASR[31:28] contain the version number, we left-shift that off # CASR[27:2] and CASR[0] are always 0 # CASR[1] is the DPE bit, which equals 1 if parity error or 0 if no error ldr r0, [r3, #(((STR+CASR)-(LDR+CA0))<<2)] @ load CASR lsls r0, #4 @ shift off version number beq mmcau_des_chk_parity_end @ check the DPE bit # if parity error, movs r0, #1 negs r0, r0 @ return -1 # else (no error), mmcau_des_chk_parity_end: bx lr @ return 0 # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # MMCAU_DES_ENCRYPT # Encrypts a single 8-byte block # # ARGUMENTS # *in pointer to 8-byte block of input plaintext # *key pointer to 64-bit DES key with parity bits # *out pointer to 8-byte block of output ciphertext # # NOTE # Input and output blocks may overlap # # CALLING CONVENTION # void mmcau_des_encrypt (const unsigned char *in, # const unsigned char *key, # unsigned char *out) # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # REGISTER | ALLOCATION (at the start of mmcau_des_encrypt) # -----------+------------------------------------------------------------ # r0 | *in (arg0) # r1 | *key (arg1) # r2 | *out (arg2) # | # > r2 | irrelevant # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # .global _mmcau_des_encrypt .global mmcau_des_encrypt .type mmcau_des_encrypt, %function .align 4 _mmcau_des_encrypt: mmcau_des_encrypt: # store regs r4-r7, we need to restore them at the end of the routine push {r4-r7} @ store regs # load the 64-bit key into the CAU's CA0/CA1 regs # load the 64-bit plaintext input block into the CAU's CA2/CA3 regs ldr r7, =MMCAU_PPB_INDIRECT+((LDR+CA0)<<2) ldmia r1!, {r3-r4} @ load key rev r3, r3 rev r4, r4 ldmia r0!, {r5-r6} @ load plaintext rev r5, r5 rev r6, r6 stmia r7!, {r3-r6} @ store in CA[0-3] # send a series of 17 direct cau commands to perform the DES round operations # *(MMCAU_PPB_DIRECT) = mmcau_3_cmds(DESK,DESR+IP+KSL1,DESR+KSL2) 1- 3 # *(MMCAU_PPB_DIRECT) = mmcau_3_cmds(DESR+KSL2,DESR+KSL2,DESR+KSL2) 4- 6 # *(MMCAU_PPB_DIRECT) = mmcau_3_cmds(DESR+KSL2,DESR+KSL2,DESR+KSL1) 7- 9 # *(MMCAU_PPB_DIRECT) = mmcau_3_cmds(DESR+KSL2,DESR+KSL2,DESR+KSL2) 10-12 # *(MMCAU_PPB_DIRECT) = mmcau_3_cmds(DESR+KSL2,DESR+KSL2,DESR+KSL2) 13-15 # *(MMCAU_PPB_DIRECT) = mmcau_2_cmds(DESR+KSL1,DESR+FP) 16-17 ldr r0, =encrypt_reg_data ldmia r0, {r0-r1, r3-r6} @ load commands str r3, [r0] @ send commands 1- 3 str r4, [r0] @ " " 4- 6 str r5, [r0] @ " " 7- 9 str r4, [r0] @ " " 10-12 str r4, [r0] @ " " 13-15 str r6, [r0] @ " " 16-17 # store the 64-bit ciphertext output block into memory ldmia r1, {r0-r1} @ load ciphertext rev r0, r0 rev r1, r1 stmia r2!, {r0-r1} @ store in out[0-1] pop {r4-r7} @ restore regs bx lr @ exit routine # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # MMCAU_DES_DECRYPT # Decrypts a single 8-byte block # # ARGUMENTS # *in pointer to 8-byte block of input ciphertext # *key pointer to 64-bit DES key with parity bits # *out pointer to 8-byte block of output plaintext # # NOTE # Input and output blocks may overlap # # CALLING CONVENTION # void mmcau_des_decrypt (const unsigned char *in, # const unsigned char *key, # unsigned char *out) # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # REGISTER | ALLOCATION (at the start of mmcau_des_decrypt) # -----------+------------------------------------------------------------ # r0 | *in (arg0) # r1 | *key (arg1) # r2 | *out (arg2) # | # > r2 | irrelevant # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # .global _mmcau_des_decrypt .global mmcau_des_decrypt .type mmcau_des_decrypt, %function .align 4 _mmcau_des_decrypt: mmcau_des_decrypt: # store regs r4-r7, we need to restore them at the end of the routine push {r4-r7} @ store regs # load the 64-bit key into the CAU's CA0/CA1 regs # load the 64-bit ciphertext input block into the CAU's CA2/CA3 regs ldr r7, =MMCAU_PPB_INDIRECT+((LDR+CA0)<<2) ldmia r1!, {r3-r4} @ load key rev r3, r3 rev r4, r4 ldmia r0!, {r5-r6} @ load ciphertext rev r5, r5 rev r6, r6 stmia r7!, {r3-r6} @ store in CA[0-3] # send a series of 17 direct cau commands to perform the DES round operations # *(MMCAU_PPB_DIRECT) = mmcau_3_cmds(DESK+DC,DESR+IP+KSR1,DESR+KSR2) 1- 3 # *(MMCAU_PPB_DIRECT) = mmcau_3_cmds(DESR+KSR2,DESR+KSR2,DESR+KSR2) 4- 6 # *(MMCAU_PPB_DIRECT) = mmcau_3_cmds(DESR+KSR2,DESR+KSR2,DESR+KSR1) 7- 9 # *(MMCAU_PPB_DIRECT) = mmcau_3_cmds(DESR+KSR2,DESR+KSR2,DESR+KSR2) 10-12 # *(MMCAU_PPB_DIRECT) = mmcau_3_cmds(DESR+KSR2,DESR+KSR2,DESR+KSR2) 13-15 # *(MMCAU_PPB_DIRECT) = mmcau_2_cmds(DESR+KSR1,DESR+FP) 16-17 ldr r0, =decrypt_reg_data ldmia r0, {r0-r1, r3-r6} @ load commands str r3, [r0] @ send commands 1- 3 str r4, [r0] @ " " 4- 6 str r5, [r0] @ " " 7- 9 str r4, [r0] @ " " 10-12 str r4, [r0] @ " " 13-15 str r6, [r0] @ " " 16-17 # store the 64-bit plaintext output block into memory ldmia r1, {r0-r1} @ load plaintext rev r0, r0 rev r1, r1 stmia r2!, {r0-r1} @ store in out[0-1] pop {r4-r7} @ restore regs bx lr @ exit routine # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # .data .type encrypt_reg_data, %object .align 4 encrypt_reg_data: .word MMCAU_PPB_DIRECT @ r0 .word MMCAU_PPB_INDIRECT+((STR+CA2)<<2) @ r1 .word MMCAU_3_CMDS+((DESK)<<22)+((DESR+IP+KSL1)<<11)+DESR+KSL2 @ r3 .word MMCAU_3_CMDS+((DESR+KSL2)<<22)+((DESR+KSL2)<<11)+DESR+KSL2 @ r4 .word MMCAU_3_CMDS+((DESR+KSL2)<<22)+((DESR+KSL2)<<11)+DESR+KSL1 @ r5 .word MMCAU_2_CMDS+((DESR+KSL1)<<22)+((DESR+FP)<<11) @ r6 .type decrypt_reg_data, %object .align 4 decrypt_reg_data: .word MMCAU_PPB_DIRECT @ r0 .word MMCAU_PPB_INDIRECT+((STR+CA2)<<2) @ r1 .word MMCAU_3_CMDS+((DESK+DC)<<22)+((DESR+IP+KSR1)<<11)+DESR+KSR2 @ r3 .word MMCAU_3_CMDS+((DESR+KSR2)<<22)+((DESR+KSR2)<<11)+DESR+KSR2 @ r4 .word MMCAU_3_CMDS+((DESR+KSR2)<<22)+((DESR+KSR2)<<11)+DESR+KSR1 @ r5 .word MMCAU_2_CMDS+((DESR+KSR1)<<22)+((DESR+FP)<<11) @ r6