zasm: Read from and write to streams instead of memory

apps/zasm/io.asm

@@ -0,0 +1,69 @@
+; *** Consts ***
+.equ	IO_MAX_LINELEN	0xff
+; *** Variables ***
+ioGetCPtr:
+	.fill 2
+ioPutCPtr:
+	.fill 2
+ioLineBuf:
+	.fill IO_MAX_LINELEN+1
+
+; *** Code ***
+
+ioGetC:
+	ld	ix, (ioGetCPtr)
+	jp	(ix)
+
+ioPutC:
+	ld	ix, (ioPutCPtr)
+	jp	(ix)
+
+; Sets Z is A is CR, LF, or null.
+isLineEnd:
+	or	a	; same as cp 0
+	ret	z
+	cp	0x0d
+	ret	z
+	cp	0x0a
+	ret
+
+; Read a single line from ioGetCPtr and place it in ioLineBuf.
+; Returns number of chars read in A. 0 means we're at the end of our input
+; stream, which happens when GetC unsets Z. Make HL point to ioLineBuf.
+; We ignore empty lines and pass through them like butter.
+; A null char is written at the end of the line.
+ioReadLine:
+	push	bc
+	; consume ioGetC as long as it yields a line end char.
+.loop1:
+	call	ioGetC
+	jr	nz, .eof	; GetC unsets Z? We don't have a line to read,
+				; we have EOF.
+	call	isLineEnd
+	jr	z, .loop1
+	; A contains the first char of our line.
+	ld	c, 1
+	ld	(ioLineBuf), a
+	ld	hl, ioLineBuf+1
+.loop2:
+	call	ioGetC
+	call	isLineEnd
+	jr	z, .success	; We have end of line
+	ld	(hl), a
+	inc	hl
+	inc	c
+	jr	.loop2
+
+.success:
+	; write null char at HL before we return
+	xor	a
+	ld	(hl), a
+	ld	a, c
+	ld	hl, ioLineBuf
+	jr	.end
+.eof:
+	xor	a
+.end:
+	pop	bc
+	ret
+

apps/zasm/main.asm

@@ -1,4 +1,5 @@
 ; *** Requirements ***
+; blockdev
 ; JUMP_STRNCMP
 ; JUMP_ADDDE
 ; JUMP_UPCASE
@@ -6,23 +7,23 @@
 ; JUMP_INTODE
 
 ; *** Code ***
-; Parse asm file in (HL) and outputs its upcodes in (DE). Returns the number
-; of bytes written in C.
+; Read file through GetC routine pointer at HL and outputs its upcodes through
+; the PutC routine pointer at DE.
 main:
-	ld	bc, 0		; C is our written bytes counter
+	ld	(ioGetCPtr), hl
+	ld	(ioPutCPtr), de
 .loop:
+	call	ioReadLine
+	or	a		; is A 0?
+	jr	z, .stop	; We have EOF
 	call	parseLine
 	jr	nz, .stop
-	ld	a, c
-	add	a, ixl
-	ld	c, a
-	call	gotoNextLine
-	jr	nz, .stop	; error? stop
 	jr	.loop
 .stop:
 	ret
 
 #include "util.asm"
+#include "io.asm"
 #include "parse.asm"
 #include "literal.asm"
 #include "instr.asm"
@@ -36,38 +37,38 @@ main:
 parseLine:
 	push	bc
 
-	call	gotoNextNotBlankLine
-	jr	nz, .error
 	call	tokenize
 	ld	a, b		; TOK_*
 	cp	TOK_INSTR
 	jr	z, .instr
 	cp	TOK_DIRECTIVE
 	jr	z, .direc
+	cp	TOK_EMPTY
+	jr	z, .success	; empty line? do nothing but don't error out.
 	jr	.error		; token not supported
 .instr:
 	ld	a, c		; I_*
 	call	parseInstruction
 	or	a	; is zero?
 	jr	z, .error
-	ld	b, 0
-	ld	c, a	; written bytes
-	push	hl
+	ld	b, a
 	ld	hl, instrUpcode
-	call	copy
-	pop	hl
-	call	JUMP_ADDDE
+.loopInstr:
+	ld	a, (hl)
+	call	ioPutC
+	inc	hl
+	djnz	.loopInstr
 	jr	.success
 .direc:
 	ld	a, c		; D_*
 	call	parseDirective
-	ld	b, 0
-	ld	c, a	; written bytes
-	push	hl
+	ld	b, a
 	ld	hl, direcData
-	call	copy
-	pop	hl
-	call	JUMP_ADDDE
+.loopDirec:
+	ld	a, (hl)
+	call	ioPutC
+	inc	hl
+	djnz	.loopDirec
 	jr	.success
 .success:
 	ld	ixl, a

apps/zasm/parse.asm

@@ -6,19 +6,11 @@ scratchpad:
 
 ; *** Code ***
 
-; Sets Z is A is ';', CR, LF, or null.
+; Sets Z is A is ';' or null.
 isLineEndOrComment:
 	cp	';'
 	ret	z
-	; Continues onto isLineEnd...
-
-; Sets Z is A is CR, LF, or null.
-isLineEnd:
-	or	a	; same as cp 0
-	ret	z
-	cp	0x0d
-	ret	z
-	cp	0x0a
+	or	a	; cp 0
 	ret
 
 ; Sets Z is A is ' ' '\t' or ','
@@ -81,48 +73,3 @@ toWord:
 .success:
 	xor	a	; ensure Z
 	ret
-
-; Advance HL to the beginning of the next line, that is, right after the next
-; 0x10 or 0x13 or both. If we reach null, we stop and error out.
-; Sets Z on success, unsets it on error.
-gotoNextLine:
-	dec	hl	; a bit weird, but makes the looping easier
-.loop:
-	inc	hl
-	ld	a, (hl)
-	call	isLineEnd
-	jr	nz, .loop
-	; (HL) is 0x10, 0x13 or 0
-	or	a	; is 0?
-	jr	z, .error
-	; we might have 0x13 followed by 0x10, let's account for this.
-	; Yes, 0x10 followed by 0x10 will make us skip two lines, but this is of
-	; no real consequence in our context.
-	inc	hl
-	ld	a, (hl)
-	call	isLineEnd
-	jr	nz, .success
-	or	a	; is 0?
-	jr	z, .error
-	; There was another line sep. Skip this char
-	inc	hl
-	; Continue on to .success
-.success:
-	xor	a	; ensure Z
-	ret
-.error:
-	call	JUMP_UNSETZ
-	ret
-
-; Repeatedly calls gotoNextLine until the line in (HL) points to a line that
-; isn't blank or 100% comment. Sets Z if we reach a line, Unset Z if we reach
-; EOF
-gotoNextNotBlankLine:
-	call	toWord
-	ret	z	; Z set? we have a not-blank line
-	; Z not set? (HL) is at the end of the line or at the beginning of
-	; comments.
-	call	gotoNextLine
-	ret	nz
-	jr	gotoNextNotBlankLine
-

apps/zasm/tok.asm

@@ -4,6 +4,7 @@
 ; *** Consts ***
 TOK_INSTR	.equ	0x01
 TOK_DIRECTIVE	.equ	0x02
+TOK_EMPTY	.equ	0xfe	; not a bad token, just an empty line
 TOK_BAD		.equ	0xff
 
 ; *** Code ***
@@ -14,6 +15,7 @@ TOK_BAD		.equ	0xff
 ; If no token matches, TOK_BAD is written to B
 tokenize:
 	call	toWord
+	jr	nz, .emptyline
 	call	readWord
 	push	hl		; Save advanced HL for later
 	ld	hl, scratchpad
@@ -33,3 +35,7 @@ tokenize:
 	ld	c, a
 	pop	hl
 	ret
+.emptyline:
+	ld	b, TOK_EMPTY
+	; no HL to pop, we jumped before the push
+	ret

apps/zasm/util.asm

@@ -8,27 +8,6 @@ rlaX:
 	djnz	.loop
 	ret
 
-; Copy BC bytes from (HL) to (DE).
-copy:
-	; first, let's see if BC is zero. if it is, we have nothing to do.
-	; remember: 16-bit inc/dec don't modify flags. that's why we check B
-	; and C separately.
-	inc	b
-	dec	b
-	jr	nz, .proceed
-	inc	c
-	dec	c
-	ret	z	; zero? nothing to do
-.proceed:
-	push	bc
-	push	de
-	push	hl
-	ldir
-	pop	hl
-	pop	de
-	pop	bc
-	ret
-
 callHL:
 	jp	(hl)
 	ret

tools/emul/Makefile

@@ -1,5 +1,6 @@
 TARGETS = shell zasm
 KERNEL_HEADERS = shell-kernel.h zasm-kernel.h
+USER_HEADERS = zasm-user.h
 
 .PHONY: all
 all: $(TARGETS)
@@ -23,4 +24,4 @@ libz80/libz80.o: libz80/z80.c
 
 .PHONY: clean
 clean:
-	rm -f $(TARGETS) $(KERNEL_HEADERS)
+	rm -f $(TARGETS) $(KERNEL_HEADERS) $(USER_HEADERS)

tools/emul/zasm_glue.asm

@@ -1,8 +1,6 @@
 ; Glue code for the emulated environment
 .equ USER_CODE		0x4000
 .equ RAMEND		0xffff
-.equ ZASM_INPUT		0xa000
-.equ ZASM_OUTPUT	0xd000
 .equ STDIO_PORT		0x00
 
 jr	init	; 2 bytes
@@ -17,35 +15,24 @@ init:
 	di
 	ld	hl, RAMEND
 	ld	sp, hl
-	ld	hl, ZASM_INPUT
-	; yes, this means that input can't have null bytes
-.inloop:
-	in	a, (STDIO_PORT)
-	ld	(hl), a		; before cond jr so we write a final \0
-	or	a
-	jr	z, .inloopend
-	inc	hl
-	jr	.inloop
-.inloopend:
-	ld	hl, ZASM_INPUT
-	ld	de, ZASM_OUTPUT
+	ld	hl, emulGetC
+	ld	de, emulPutC
 	call	USER_CODE
-	; BC contains the number of written bytes
-	xor	a
-	cp	b
-	jr	nz, .spit
-	cp	c
-	jr	z, .end		; no output
-.spit:
-	ld	hl, ZASM_OUTPUT
-.outloop:
-	ld	a, (hl)
-	out	(STDIO_PORT), a
-	cpi			; a trick to inc HL and dec BC at the same time.
-				; P/V indicates whether BC reached 0
-	jp	pe, .outloop	; BC is not zero, loop
-.end:
 	; signal the emulator we're done
 	halt
 
+emulGetC:
+	in	a, (STDIO_PORT)
+	or	a		; cp 0
+	jr	z, .eof
+	cp	a		; ensure z
+	ret
+.eof:
+	call	unsetZ
+	ret
+
+emulPutC:
+	out	(STDIO_PORT), a
+	ret
+
 #include "core.asm"