; 
; potentially popular macros for the macross assembler
; 
; 11-Jan-85	cbm	converted for Macross from original a65
; 

mif (!isDefined(_macros_)) {
	define _macros_ = 1
;
; push and pop X and Y registers
;
macro phx {
	txa
	pha
}
macro plx {
	pla
	tax
}
macro phy {
	tya
	pha
}
macro ply {
	pla
	tay
}

macro call arg {
	jsr arg
}

macro return {
	rts
}

macro callret arg {
	jmp arg		; same as jsr arg; rts
}

macro save arg {
	lda arg
	pha
}

macro restore arg {
	pla
	sta arg
}

; ================================================================
; some auxiliary functions for the macros that follow
;

; MAKE-FIRST-BYTE - access low byte for any addressing mode
function makeFirstByte(operand) {
	mif (isImmediateMode(operand)) {
		freturn(/operand)
	} melse {
		freturn(operand)
	}
}

; MAKE-SECOND-BYTE - access high byte for any addr mode except (post y zzz)
function makeSecondByte(operand) {
	mif (isImmediateMode(operand)) {
		freturn(?operand)
	} melse {
		freturn(operand + 1)
	}
}

; MAKE-NTH-BYTE - similarly access arbitrary byte
function makeNthByte(operand, n) {
	mif (isImmediateMode(operand)) {
		freturn((operand >> (8 * (n - 1))) & 0xFF)
	} melse {
		freturn(operand + n - 1)
	}
}

; ================================================================
; MOVM, MOVEB, MOVB, MOVEW, MOVW, CLEARB, and CLEARW
; Note that the args on MOVEx are src,dst as opposed to
; MOVx, which uses dst,src.
; 

; MOVM - move multiple 
macro	movm	n, dst, src {
	mvariable i
	mfor (i=1, i<=n, i++) {
		lda	makeNthByte(src, i)
		sta	makeNthByte(dst, i)
	}
}

; MOVEB - move byte from src to dst
macro	moveb	src, dst {
	lda 	src
	sta	dst
}

; MOVB - for those who like their destination before their source
macro	movb  dst, src {
	lda	src
	sta	dst
}

; MOVEW - move word from src to dst
;	works for all addressing moves EXCEPT (post y zzz)
macro	movew	src, dst {
	lda	makeFirstByte(src) 
	sta	makeFirstByte(dst)
	lda	makeSecondByte(src)
	sta	makeSecondByte(dst)
}

; MOVW - and another with destination before source
;	works for all addressing moves EXCEPT (post y zzz)
macro	movw  dst, src {
	lda	makeFirstByte(src)
	sta	makeFirstByte(dst)
	lda	makeSecondByte(src)
	sta	makeSecondByte(dst)
}

; CLEARB - zero byte dst
macro	clearb	dst {
	lda	#0
	sta	dst
}

; CLEARW - zero word dst
;	works for all addressing modes EXCEPT (post y dst)
macro	clearw	dst {
	lda	#0
	sta	makeFirstByte(dst)
	sta	makeSecondByte(dst)
}

; ================================================================
; the general macros
; 

; MOVWB - move byte SRC to word DST
; 	works for all addressing modes EXCEPT (post y zzz)
macro	movwb	dst, src {
	lda	src
	sta	makeFirstByte(dst)
	lda	#0
	sta	makeSecondByte(dst)
}

; ADDM - add multiple 
macro	addm	n, dst, src, src1 {
	mvariable i
	clc
	mfor (i=1, i<=n, i++) {
		lda	makeNthByte(src, i)
		adc	makeNthByte(src1, i)
		sta	makeNthByte(dst, i)
	}
}

; ADDB - byte dst = byte src0 + byte src1
macro	addb	dst, src0, src1 {
	clc
	lda	src0
	adc	src1
	sta	dst
}

; ADDW - word dst = word src0 + word src1
;	works for all addressing modes EXCEPT (post y zzz)
macro	addw	dst, src0, src1 {
	clc
	lda	makeFirstByte(src0)
	adc	makeFirstByte(src1)
	sta	makeFirstByte(dst)
	lda	makeSecondByte(src0)
	adc	makeSecondByte(src1)
	sta	makeSecondByte(dst)
}

; ADDWWB - word dst = word src0 + byte src1
;	works for all addressing modes EXCEPT (post y zzz)
macro	addwwb	dst, src0, src1 {
	clc
	lda	makeFirstByte(src0)
	adc	src1
	sta	makeFirstByte(dst)
	lda	makeSecondByte(src0)
	adc	#0
	sta	makeSecondByte(dst)
}

; SUBB - byte dst = byte src0 - byte src1
macro	subb	dst, src0, src1 {
	sec
	lda	src0
	sbc	src1
	sta	dst
}

; SUBW - word dst = word src0 - word src1
;	works for all addressing modes EXCEPT (post y zzz)
macro	subw	dst, src0, src1 {
	sec
	lda	makeFirstByte(src0)
	sbc	makeFirstByte(src1)
	sta	makeFirstByte(dst)
	lda	makeSecondByte(src0)
	sbc	makeSecondByte(src1)
	sta	makeSecondByte(dst)
}

; SUBWWB - word dst = word src0 - byte src1
;	works for all addressing modes EXCEPT (post y zzz)
macro	subwwb	dst, src0, src1 {
	sec
	lda	makeFirstByte(src0)
	sbc	src1
	sta	makeFirstByte(dst)
	lda	makeSecondByte(src0)
	sbc	#0
	sta	makeSecondByte(dst)
}

; ================================================================
; cmpm, cmpb, cmpw
; 	compare two quantities (arbitrary length, byte, and word)
; 	set the condition flags following s0-s1
; 
macro	cmpm	n, s0, s1 {
	mvariable i
	mfor (i=1, i<=n, i++) {
		lda	makeNthByte(s0, i)
		sbc	makeNthByte(s1, i)
	}
}

macro	cmpb	s0, s1 {
	sec
	lda	s0
	sbc	s1
}

macro	cmpw	s0, s1 {
	sec
	lda	makeFirstByte(s0)
	sbc	makeFirstByte(s1)
	lda	makeSecondByte(s0)
	sbc	makeSecondByte(s1)
}

;
; ASLM - multiply all by 2
macro	aslm	n, s0 {
	mvariable i
	asl s0
	mfor (i = 2, i <= n, i++) {
		rol	makeNthByte(s0, i)
	}
}

; ================================================================
; asrm, asrb, asrw
; 	Arithmetic Shift Right (with sign extend).
; 
macro	asrm	n, s0 {
	mvariable i = n
	lda	makeNthByte(s0, i)
	cmp	#0x80
	mwhile (i > 0) {
		ror	makeNthByte(s0, i--)
	}
}

macro	asrb	s0 {
	lda	s0
	cmp	#0x80
	ror	s0
}

macro	asrw	s0 {
	lda	makeSecondByte(s0)
	cmp	#0x80
	ror	makeSecondByte(s0)
	ror	makeFirstByte(s0)
}

; ================================================================
; repeat n {code. . .}
; 	repeat n instances of code.  e.g.,
;	repeat 6 {
; 		lda	x[foo]
; 		sta	x[bar]
; 		inx
;	}
; 	will generate inline code to move 6 bytes
; 
macro	repeat	count, blockToRepeat {
	mvariable i = count
	mwhile (i-- > 0) {
		blockToRepeat
	}
}

macro	includef fname {
	printf("Including %s\n", fname)
	include	fname
}


}  ; *** end -- mif (!isDefined(_macros_)) ***