fileio.s

@ Various macros to perform file I/O
@ The fd parameter needs to be a register.
@ Uses R0, R1, R7.
@ Return code is in R0.


.equ O_RDONLY, 0
.equ O_WRONLY, 1
.equ O_CREAT, 0100
.equ S_RDWR, 0666

.macro openFile fileName, flags
	ldr r0, =\fileName
	mov r1, #\flags
	mov r2, #S_RDWR @ RW access rights
	mov r7, #sys_open
	svc 0
.endm

.macro readFile fd, buffer, length
	mov r0, \fd @ file descriptor
	ldr r1, =\buffer
	mov r2, #\length
	mov r7, #sys_read	
	svc 0
.endm

.macro writeFile fd, buffer, length
	mov r0, \fd @ file descriptor
	ldr r1, =\buffer
	mov r2, \length
	mov r7, #sys_write
	svc 0
.endm

.macro flushClose fd
	@fsync syscall
	mov r0, \fd
	mov r7, #sys_fsync
	svc 0
	@close syscall
	mov r0, \fd
	mov r7, #sys_close
	svc 0
.endm