copybuf.asm

maxim的对sd卡的串行spi模式进行读写操作控制的程序源码

;===========================================================================
;=
;=  Copyright (C) 2006 MAXIM/Dallas Semiconductor Corporation. 
;=  All rights Reserved. Printed in U.S.A.
;=
;=  Permission is hereby granted, free of charge, to any person obtaining a
;=  copy of this software and associated documentation files (the 
;=  "Software"), to deal in the Software without restriction, including
;=  without limitation the rights to use, copy, modify, merge, publish,
;=  distribute, sublicense, and/or sell copies of the Software, and to
;=  permit persons to whom the Software is furnished to do so, subject to
;=  the following conditions:
;=  
;=  The above copyright notice and this permission notice shall be included
;=  in all copies or substantial portions of the Software source code.
;=  
;=  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
;=  OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
;=  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
;=  IN NO EVENT SHALL MAXIM/DALLAS SEMICONDUCTOR BE LIABLE FOR ANY CLAIM, 
;=  DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR 
;=  OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR 
;=  THE USE OR OTHER DEALINGS IN THE SOFTWARE.
;=
;=  Except as contained in this notice, the name of MAXIM/Dallas 
;=  Semiconductor shall not be used except as stated in the MAXIM/Dallas 
;=  Semiconductor Branding Policy.
;=
;=     Description: MAXQ2000 Secure Digital (SD) Card Interface via SPI
;=                 
;=        Filename: copybuf.asm
;=
;=        Compiler: Rowley CrossWorks assembler
;=
;=        Hardware: MAXQ2000 Evaluation Kit (Rev B)
;=
;===========================================================================

urom_copyBuffer	EQU	(0x84a2 << 1)
	
	public _asm_copybuffer

; int A[7] asm_copybuffer(unsigned char *dstaddr A[7], const __code char *srcaddr A[6], int len A[5])
;
; Copy n bytes from flash into the provided RAM buffer

	code
	even
_asm_copybuffer:
	move	DPC, #0x00	; All pointers in byte mode, DP[0] active
	move	AP, #7		; Point ACC to first argument, which is also
				;  where we will deposit the return value

	move	BP, ACC		; No translation needed for RAM address
	move	OFFS, #0	; Destination in BP[Offs]

	
	move	ACC, A[6]	; Set ACC to the flash src address
	or	#0x8000		; Translate address. In ROM execution,
				;  flash memory begins at 0x8000
	move	DP[0], ACC	; Source goes into DP[0]

	move	ACC, A[5]	; Length is bytes to copy
	move	LC[0], ACC	;  and goes into LC[0]

	call	urom_copyBuffer	; Call the Utility ROM helper function
				;  to execute the actual copy
	
	move	DPC, #0x18	; Restore DPC to the Rowley value
	ret