📄 lib_mem_a.asm
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;********************************************************************************************************; uC/LIB; CUSTOM LIBRARY MODULES;; (c) Copyright 2004-2007; Micrium, Inc.; Weston, FL;; All rights reserved. Protected by international copyright laws.;; uC/LIB is provided in source form for FREE evaluation, for educational; use or peaceful research. If you plan on using uC/LIB in a commercial; product you need to contact Micrium to properly license its use in your; product. We provide ALL the source code for your convenience and to; help you experience uC/LIB. The fact that the source code is provided; does NOT mean that you can use it without paying a licensing fee.;; Knowledge of the source code may NOT be used to develop a similar product.;; Please help us continue to provide the Embedded community with the finest; software available. Your honesty is greatly appreciated.;********************************************************************************************************;********************************************************************************************************;; STANDARD MEMORY OPERATIONS;; ARM; IAR Compiler;;; Filename : lib_mem_a.asm; Version : V1.24; Programmer(s) : JDH;********************************************************************************************************; Note(s) : (1) NO compiler-supplied standard library functions are used in library or product software.;; (a) ALL standard library functions are implemented in the custom library modules :;; (1) \<Custom Library Directory>\lib*.*;; (2) \<Custom Library Directory>\Ports\<cpu>\<compiler>\lib*_a.*;; where; <Custom Library Directory> directory path for custom library software; <cpu> directory name for specific processor (CPU); <compiler> directory name for specific compiler;; (b) Product-specific library functions are implemented in individual products.;; (2) Assumes ARM CPU mode configured for Little Endian.;********************************************************************************************************;********************************************************************************************************; PUBLIC FUNCTIONS;******************************************************************************************************** PUBLIC Mem_Copy;********************************************************************************************************; CODE GENERATION DIRECTIVES;******************************************************************************************************** RSEG CODE:CODE:NOROOT(2) CODE32;$PAGE ;********************************************************************************************************; Mem_Copy();; Description : Copy data octets from one buffer to another buffer.;; Argument(s) : pdest Pointer to destination memory buffer.;; psrc Pointer to source memory buffer.;; size Number of data buffer octets to copy.;; Return(s) : none.;; Caller(s) : various.;; Note(s) : (1) Null copies allowed (i.e. 0-octet size).;; (2) Memory buffers NOT checked for overlapping.;; (3) Modulo arithmetic is used to determine whether a memory buffer starts on a 'CPU_ALIGN'; address boundary.;********************************************************************************************************; void Mem_Copy (void *pdest, ; ==> R0; void *psrc, ; ==> R1; CPU_SIZE_T size) ; ==> R2Mem_Copy: CMP R0, #0 BNE Mem_Copy_1 BX LR ; return if pdest == NULLMem_Copy_1: CMP R1, #0 BNE Mem_Copy_2 BX LR ; return if psrc == NULLMem_Copy_2: CMP R2, #0 BNE Mem_Copy_3 BX LR ; return if size == 0Mem_Copy_3: STMFD SP!, {R3-R12} ; save registers on stack;$PAGE Chk_Align_32: ; check if both dest & src 32-bit aligned AND R3, R0, #0x03 AND R4, R1, #0x03 CMP R3, R4 BNE Chk_Align_16 ; not 32-bit aligned, check for 16-bit alignment RSB R3, R3, #0x04 ; compute 1-2-3 pre-copy bytes (to align to the next 32-bit boundary) AND R3, R3, #0x03Pre_Copy_1: CMP R3, #1 ; copy 1-2-3 bytes (to align to the next 32-bit boundary) BCC Copy_32_1 ; start real 32-bit copy CMP R2, #1 ; check if any more data to copy BCC Mem_Copy_END ; no more data to copy LDRB R4, [R1], #1 STRB R4, [R0], #1 SUB R3, R3, #1 SUB R2, R2, #1 B Pre_Copy_1Chk_Align_16: ; check if both dest & src 16-bit aligned AND R3, R0, #0x01 AND R4, R1, #0x01 CMP R3, R4 BNE Copy_08_1 ; not 16-bit aligned, start 8-bit copyPre_Copy_2: CMP R3, #1 ; copy 1 byte (to align to the next 16-bit boundary) BCC Copy_16_1 ; start real 16-bit copy LDRB R4, [R1], #1 STRB R4, [R0], #1 SUB R3, R3, #1 SUB R2, R2, #1 B Pre_Copy_2Copy_32_1: CMP R2, #(04*10*09) ; Copy 9 chunks of 10 32-bit words (360 octets per loop) BCC Copy_32_2 LDMIA R1!, {R3-R12} STMIA R0!, {R3-R12} LDMIA R1!, {R3-R12} STMIA R0!, {R3-R12} LDMIA R1!, {R3-R12} STMIA R0!, {R3-R12} LDMIA R1!, {R3-R12} STMIA R0!, {R3-R12} LDMIA R1!, {R3-R12} STMIA R0!, {R3-R12} LDMIA R1!, {R3-R12} STMIA R0!, {R3-R12} LDMIA R1!, {R3-R12} STMIA R0!, {R3-R12} LDMIA R1!, {R3-R12} STMIA R0!, {R3-R12} LDMIA R1!, {R3-R12} STMIA R0!, {R3-R12} SUB R2, R2, #(04*10*09) B Copy_32_1Copy_32_2: CMP R2, #(04*10*01) ; Copy chunks of 10 32-bit words (40 octets per loop) BCC Copy_32_3 LDMIA R1!, {R3-R12} STMIA R0!, {R3-R12} SUB R2, R2, #(04*10*01) B Copy_32_2Copy_32_3: CMP R2, #(04*01*01) ; Copy remaining 32-bit words BCC Copy_16_1 LDR R3, [R1], #4 STR R3, [R0], #4 SUB R2, R2, #(04*01*01) B Copy_32_3;$PAGE Copy_16_1: CMP R2, #(02*01*16) ; Copy chunks of 16 16-bit words (32 bytes per loop) BCC Copy_16_2 LDRH R3, [R1], #2 STRH R3, [R0], #2 LDRH R3, [R1], #2 STRH R3, [R0], #2 LDRH R3, [R1], #2 STRH R3, [R0], #2 LDRH R3, [R1], #2 STRH R3, [R0], #2 LDRH R3, [R1], #2 STRH R3, [R0], #2 LDRH R3, [R1], #2 STRH R3, [R0], #2 LDRH R3, [R1], #2 STRH R3, [R0], #2 LDRH R3, [R1], #2 STRH R3, [R0], #2 LDRH R3, [R1], #2 STRH R3, [R0], #2 LDRH R3, [R1], #2 STRH R3, [R0], #2 LDRH R3, [R1], #2 STRH R3, [R0], #2 LDRH R3, [R1], #2 STRH R3, [R0], #2 LDRH R3, [R1], #2 STRH R3, [R0], #2 LDRH R3, [R1], #2 STRH R3, [R0], #2 LDRH R3, [R1], #2 STRH R3, [R0], #2 LDRH R3, [R1], #2 STRH R3, [R0], #2 SUB R2, R2, #(02*01*16) B Copy_16_1Copy_16_2: CMP R2, #(02*01*01) ; Copy remaining 16-bit words BCC Copy_08_1 LDRH R3, [R1], #2 STRH R3, [R0], #2 SUB R2, R2, #(02*01*01) B Copy_16_2;$PAGE Copy_08_1: CMP R2, #(01*01*16) ; Copy chunks of 16 8-bit words (16 bytes per loop) BCC Copy_08_2 LDRB R3, [R1], #1 STRB R3, [R0], #1 LDRB R3, [R1], #1 STRB R3, [R0], #1 LDRB R3, [R1], #1 STRB R3, [R0], #1 LDRB R3, [R1], #1 STRB R3, [R0], #1 LDRB R3, [R1], #1 STRB R3, [R0], #1 LDRB R3, [R1], #1 STRB R3, [R0], #1 LDRB R3, [R1], #1 STRB R3, [R0], #1 LDRB R3, [R1], #1 STRB R3, [R0], #1 LDRB R3, [R1], #1 STRB R3, [R0], #1 LDRB R3, [R1], #1 STRB R3, [R0], #1 LDRB R3, [R1], #1 STRB R3, [R0], #1 LDRB R3, [R1], #1 STRB R3, [R0], #1 LDRB R3, [R1], #1 STRB R3, [R0], #1 LDRB R3, [R1], #1 STRB R3, [R0], #1 LDRB R3, [R1], #1 STRB R3, [R0], #1 LDRB R3, [R1], #1 STRB R3, [R0], #1 SUB R2, R2, #(01*01*16) B Copy_08_1Copy_08_2: CMP R2, #(01*01*01) ; Copy remaining 8-bit words BCC Mem_Copy_END LDRB R3, [R1], #1 STRB R3, [R0], #1 SUB R2, R2, #(01*01*01) B Copy_08_2Mem_Copy_END: LDMFD SP!, {R3-R12} ; restore registers from stack BX LR ; return END⌨️ 快捷键说明
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