* Copyright (c) 2017,2023 Stephen Heumann
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.


* Right-rotate 32-bit value in &loc (DP or 16-bit address) by &n positions
	macro
	ROTR4	&loc,&n
	aif	&n>16,.dorotl
	lda	&loc+2
	lcla	&i
&i	seta	&n
.rotrloop
	lsr	a		;to set carry
	ror	&loc
	ror	&loc+2
&i	seta	&i-1
	aif	&i>0,.rotrloop
	ago	.end
.dorotl
	ROTL4	&loc,32-&n
.end
	mend

* Expects the contents of &loc+2 to be loaded in A already
	macro
	ROTR4CONT &loc,&n
	aif	&n>16,.dorotl
	lcla	&i
&i	seta	&n
.rotrloop
	lsr	a		;to set carry
	ror	&loc
	ror	&loc+2
&i	seta	&i-1
	aif	&i>0,.rotrloop
	ago	.end
.dorotl
	ROTL4	&loc,32-&n
.end
	mend

* Left-rotate 32-bit value in &loc (DP or 16-bit address) by &n positions
	macro
	ROTL4	&loc,&n
	aif	&n>16,.dorotr2
	lda	&loc
	lcla	&i
&i	seta	&n
.rotlloop2
	asl	a		;to set carry
	rol	&loc+2
	rol	&loc
&i	seta	&i-1
	aif	&i>0,.rotlloop2
	ago	.end2
.dorotr2
	ROTR4	&loc,32-&n
.end2
	mend

* Expects the contents of &loc to be loaded in A already
	macro
	ROTL4CONT &loc,&n
	aif	&n>16,.dorotr2
	lcla	&i
&i	seta	&n
.rotlloop2
	asl	a		;to set carry
	rol	&loc+2
	rol	&loc
&i	seta	&i-1
	aif	&i>0,.rotlloop2
	ago	.end2
.dorotr2
	ROTR4	&loc,32-&n
.end2
	mend

* &to := &from ROTR4 &n
	macro
	ROTR4MOVE &to,&from,&n
	aif	&n>16,.dorotl3
	lda	&from
	sta	&to
	lda	&from+2
	sta	&to+2
	lcla	&i
&i	seta	&n
.rotrloop3
	lsr	a		;to set carry
	ror	&to
	ror	&to+2
&i	seta	&i-1
	aif	&i>0,.rotrloop3
	ago	.end3
.dorotl3
	ROTL4MOVE &to,&from,32-&n
.end3
	mend

* &to := &from ROTL4 &n
	macro
	ROTL4MOVE &to,&from,&n
	aif	&n>16,.dorotr4
	lda	&from+2
	sta	&to+2
	lda	&from
	sta	&to
	lcla	&i
&i	seta	&n
.rotlloop4
	asl	a		;to set carry
	rol	&to+2
	rol	&to
&i	seta	&i-1
	aif	&i>0,.rotlloop4
	ago	.end4
.dorotr4
	ROTR4MOVE &to,&from,32-&n
.end4
	mend

* Left-rotate with various optimizations applied
	macro
	ROTL4AUTO &loc,&n,&haveLocPlus2
	aif	&n>4,.skip1
	ROTL4	&loc,&n
	mexit
.skip1
	aif	&n>7,.skip2
	ldx	&loc+1
	lda	&loc+3
	ora	&loc-1
	sta	&loc
	stx	&loc+2
	txa
	ROTR4CONT &loc,8-&n
	mexit
.skip2
	aif	&n>11,.skip3
	ldx	&loc+1
	lda	&loc+3
	ora	&loc-1
	sta	&loc
	stx	&loc+2
	ROTL4CONT &loc,&n-8
	mexit
.skip3
	aif	&n>15,.skip4
	aif	C:&haveLocPlus2>0,.noload1
	ldy	&loc+2
	ago	.didload1
.noload1
	tay
.didload1
	lda	&loc
	sta	&loc+2
	sty	&loc
	ROTR4CONT &loc,16-&n
	mexit
.skip4
	aif	&n>16,.skip5
	aif	C:&haveLocPlus2>0,.noload2
	lda	&loc+2
.noload2
	ldy	&loc
	sta	&loc
	sty	&loc+2
	mexit
.skip5
	aif	&n>20,.skip6
	aif	C:&haveLocPlus2>0,.noload2
	lda	&loc+2
.noload2
	ldy	&loc
	sta	&loc
	sty	&loc+2
	ROTL4CONT &loc,&n-16
	mexit
.skip6
	ldx	&loc+1
	lda	&loc+3
	ora	&loc-1
	sta	&loc+2
	stx	&loc
	ROTR4CONT &loc,24-&n
	mend


* This makes a function wrapper that is callable from C,
* taking a pointer to the context structure as its argument.
	macro
	CFunction &fn
	phb
	plx
	ply
	tdc
	pld
	plb
	plb
	phy
	phx
	plb
	pha
	jsl	&fn
	pld
	rtl
	mend


* One iteration of the loop for processing blocks.
* The a,b,c,d variables are given as parameters so we can avoid cycling them.
* shift is a per-round shift amount.
	macro
	BlockLoopIter &a,&b,&c,&d,&shift

* f_0 to f_15
	aif	&part<>1,.skip1
	lda	&c
	eor	&d
	and	&b
	eor	&d
	clc
	adc	&a
	sta	temp
	
	lda	&c+2
	eor	&d+2
	and	&b+2
	eor	&d+2
	adc	&a+2
	sta	temp+2
.skip1

* f_16 to f_31
	aif	&part<>2,.skip2
	lda	&c
	tax
	ora	&d
	and	&b
	sta	temp
	txa
	and	&d
	ora	temp
	clc
	adc	&a
	tay
	
	lda	&c+2
	tax
	ora	&d+2
	and	&b+2
	sta	temp+2
	txa
	and	&d+2
	ora	temp+2
	adc	&a+2
	tax

	clc
	tya
	adc	#$7999
	sta	temp
	txa
	adc	#$5A82
	sta	temp+2
.skip2

* f_32 to f_47
	aif	&part<>3,.skip3
	lda	&b
	eor	&c
	eor	&d
	clc
	adc	&a
	tay
	
	lda	&b+2
	eor	&c+2
	eor	&d+2
	adc	&a+2
	tax

	clc
	tya
	adc	#$EBA1
	sta	temp
	txa
	adc	#$6ED9
	sta	temp+2
.skip3

	ldy	idx
	ldx	g_times_4,y
	lda	m,x
	clc
	adc	temp
	sta	temp
	inx
	inx
	lda	m,x
	adc	temp+2
	sta	temp+2
	
	iny
	iny
	sty	idx
	
	ROTL4AUTO temp,&shift,1
	
	lda	temp
	sta	&a
	lda	temp+2
	sta	&a+2
	
	mend


* One part of the loop for processing blocks (16 iterations)
	macro
	BlockLoopPart &part

loop&part anop
	
	aif	&part<>1,.skip1a
	BlockLoopIter a_,b,c,d,3
	BlockLoopIter d,a_,b,c,7
	BlockLoopIter c,d,a_,b,11
	BlockLoopIter b,c,d,a_,19
.skip1a
	aif	&part<>2,.skip2a
	BlockLoopIter a_,b,c,d,3
	BlockLoopIter d,a_,b,c,5
	BlockLoopIter c,d,a_,b,9
	BlockLoopIter b,c,d,a_,13
.skip2a
	aif	&part<>3,.skip3a
	BlockLoopIter a_,b,c,d,3
	BlockLoopIter d,a_,b,c,9
	BlockLoopIter c,d,a_,b,11
	BlockLoopIter b,c,d,a_,15
.skip3a

	lda	idx
	cmp	#16*2*&part
	bge	endloop&part
	jmp	loop&part
endloop&part anop
	mend