lcd_mem.s

来自「嵌入式系统」· S 代码 · 共 65 行

; 8 word memset

	EXPORT	LCDMemsetWord
	EXPORT	LCDMemcpyWord

	KEEP

	AREA	Memset, CODE, READONLY

; LCDMemsetWord
; r0 = pointer to destination block, r1 = source data(32bit),
; r2 = number of word width copy
LCDMemsetWord
	STMDB	r13!, {r0-r11, r14}
	ANDS	r3, r2, #7
	BEQ	octwdset
wdset
	STR	r1, [r0], #4
	SUBS	r3, r3, #1
	BNE	wdset
octwdset
	MOV	r4, r1
	MOV	r5, r1
	MOV	r6, r1
	MOV	r7, r1
	MOV	r8, r1
	MOV	r9, r1
	MOV	r10, r1
	MOV	r11, r1
	MOVS	r3, r2, LSR #3	; number of 8 words
	BEQ	fin
octset	STMIA	r0!, {r4-r11}
	SUBS	r3, r3, #1
	BNE	octset

fin	LDMIA	r13!, {r0-r11, pc}


; LCDMemcpyWord
; r0 = pointer to destination block, r1 = pointer to source,
; r2 = number of word width copy
LCDMemcpyWord
	STMFD	r13!, {r0-r12, r14}
	ANDS	r3, r2, #7
	BEQ	octwdcpy
wdcpy
	LDR	r12, [r1], #4
	STR	r12, [r0], #4
	SUBS	r3, r3, #1
	BNE	wdcpy
octwdcpy
	MOVS	r3, r2, LSR #3	; number of 8 words
	BEQ	cpyfin
octcpy	LDMFD	r1!, {r4-r11}
	STMEA	r0!, {r4-r11}
	SUBS	r3, r3, #1
	BNE	octcpy

cpyfin	LDMFD	r13!, {r0-r12, pc}


	END