*** empty log message ***

mach/z80/libsys/subr.s

@@ -0,0 +1,197 @@
+.define _read,_write,_ioctl,_getpid,_open,_close,_exit,_errno
+_read:
+	ld (savebc),bc
+	push af
+	pop bc
+	ld (saveaf),bc	! save all registers in savereg
+	ld (savede),de
+	ld (savehl),hl
+	ld (saveix),ix
+	ex	(sp),hl	! return address in hl
+	pop	bc	! skip return address
+	pop	bc	! get fd
+	ld	a,b	! check fd = 0
+	or	c
+	jr	nz,errrd
+	pop	de	! get buffer
+	pop	bc	! get count
+	ld	ix,0	! reset counter
+	push	bc
+	push	de
+	push	ix
+	push	hl	! return address
+	ex	de,hl	! buffer to hl
+1:	ld	a,b
+	or	c
+	jr	z,done	! done if count = 0
+	call	getchr
+	ld	(hl),a
+	inc	hl	! increment pointer
+	inc	ix	! increment char counter
+	dec	bc	! decrement count
+	cp	0xA
+	jr	nz,1b	! done if char = CR
+done:
+	ld bc,(saveaf)
+	push bc
+	pop af
+	ld bc,(savebc)
+	ld de,(savede)
+	ld hl,(savehl)
+	ld ix,(saveix)
+	ret
+errrd:	
+	push	bc
+	push	hl	! return address
+	ld bc,(saveaf)
+	push bc
+	pop af
+	ld bc,(savebc)
+	ld de,(savede)
+	ld hl,(savehl)
+	ld ix,(saveix)
+	ld	ix,-1
+	ret
+
+_write:
+	ld (savebc),bc
+	push af
+	pop bc
+	ld (saveaf),bc	! save all registers in savereg
+	ld (savede),de
+	ld (savehl),hl
+	ld (saveix),ix
+	ex	(sp),hl	! return address in hl
+	pop	de	! skip return address
+	pop	de	! get fd
+	ld	a,e	! check for fd = 1
+	cp	1
+	jr	nz,errwr
+	ld	a,d
+	or	a
+	jr	nz,errwr
+	pop	de      ! buffer in de
+	pop	bc	! count in bc
+	push	bc
+	push	de
+	push	de
+	push	hl
+	ex	de,hl	! buffer in hl
+	ld	e,c
+	ld	d,b	! count also in de
+1:	ld	a,b
+	or	c
+	jr	z,exit
+	ld	a,(hl)
+	call	putchr
+	inc	hl
+	dec	bc
+	jr	1b
+errwr:
+	push	de
+	push	hl
+	ld bc,(saveaf)
+	push bc
+	pop af
+	ld bc,(savebc)
+	ld de,(savede)
+	ld hl,(savehl)
+	ld ix,(saveix)
+	ld	ix,-1	! error in fd
+	ret
+exit:
+	push	de	! count on stack
+	ld bc,(saveaf)
+	push bc
+	pop af
+	ld bc,(savebc)
+	ld de,(savede)
+	ld hl,(savehl)
+	ld ix,(saveix)
+	pop	ix	! return count to caller
+	ret
+
+_ioctl:
+	ret
+_getpid:
+	ret
+
+! open return a file descriptor (0,1,2)
+! depending on 'mode'
+! mode 2 doesn't work!!
+_open:
+	ld (savebc),bc
+	push af
+	pop bc
+	ld (saveaf),bc	! save all registers in savereg
+	ld (savede),de
+	ld (savehl),hl
+	ld (saveix),ix
+	pop	bc	! return address
+	pop	de	! name pointer
+	pop	ix	! mode (0 for read,
+			! 1 for write)
+	push	ix
+	push	de
+	push	bc
+	ld bc,(saveaf)
+	push bc
+	pop af
+	ld bc,(savebc)
+	ld de,(savede)
+	ld hl,(savehl)
+	ld ix,(saveix)
+	ret		! return fd = 0 for read
+			! fd = 1 for write
+
+_close:
+	ld	ix,0	! return succes
+	ret
+_exit:
+jp 0x38
+.data
+_errno:
+	.word	0
+! output routine in monitor
+CRT	= 0x013B
+! output a charcter
+! entry: ascii character in a
+.text
+!putchr:
+!	push	hl
+!	push	bc
+!	ld	hl,tab
+!	ld	b,5
+!1:	cp	(hl)
+!	jr	z,fetch
+!	inc	hl
+!	inc	hl
+!	djnz	1b
+!2:	call	CRT
+!	pop	bc
+!	pop	hl
+!	ret
+!fetch:	inc	hl
+!	ld	a,(hl)
+!	jr	2b
+!! conversion table for nascom characters
+!tab:	.byte	0x0D,0x00
+!	.byte	0x1B,0x1E
+!	.byte	0x08,0x1D
+!	.byte	0x0A,0x1F
+!	.byte	0x7F,0x00
+
+KBD	= 0x69
+! get character from keyboard
+getchr:
+	call	KBD
+	jr	nc,getchr
+	cp	0x1F
+	jr	z,CR
+	cp	0x1D
+	jr	z,BS
+	ret
+CR:	ld	a,0xA
+	ret
+BS:	ld	a,0x8
+	ret