; memBlockRegs -- memcpy / memmove / memset keep the caller's DBR and D.
;
; unsigned short memBlockRegs(void) calls each routine down each of its
; paths (short loop, one MVN / MVP, several runs; memset short, one pass
; and over 64 KB) with DBR = $05 and D = $0100, so the routines' direct-
; page scratch lands at $01E0, and sets one bit at $02:5008 for each call
; that came back with DBR, D and dst in A:X intact.  It returns that word:
; 0x0FFF, all 12 bits, is a pass.

REGS_DBR = 0x05
REGS_D   = 0x0100
REGS_OUT = 0x025008

	.text
	.globl memBlockRegs

; The caller pushed the arguments after dst (nWords words); call fn with
; dst in A:X, drop the arguments and check what came back.
	.macro regsCall fn, dstLo, dstHi, nWords, bit
	lda #\dstLo
	ldx #\dstHi
	jsl \fn
	tay
	tsc
	clc
	adc #(\nWords * 2)
	tcs
	cpy #\dstLo
	bne .Lskip\bit
	cpx #\dstHi
	bne .Lskip\bit
	tdc
	cmp #REGS_D
	bne .Lskip\bit
	phb
	sep #0x20
	.a8
	pla
	cmp #REGS_DBR
	rep #0x20
	.a16
	bne .Lskip\bit
	lda #(1 << \bit)
	ora REGS_OUT
	sta REGS_OUT
.Lskip\bit:
	.endm

memBlockRegs:
	rep #0x30
	phb
	phd
	lda #0
	sta REGS_OUT
	pea REGS_DBR * 0x101            ; DBR twice: plb, plb
	plb
	plb
	lda #REGS_D
	tcd
	; memcpy: short, one MVN, runs (source across 03/04)
	pea 0
	pea 20
	pea 0x0002
	pea 0x6200
	regsCall memcpy, 0x6100, 0x0002, 4, 0
	pea 0
	pea 300
	pea 0x0002
	pea 0x6200
	regsCall memcpy, 0x6800, 0x0002, 4, 1
	pea 0
	pea 600
	pea 0x0003
	pea 0xff00
	regsCall memcpy, 0x7000, 0x0002, 4, 2
	; memmove backward: short, one MVP, runs (both across 03/04)
	pea 0
	pea 20
	pea 0x0002
	pea 0x6100
	regsCall memmove, 0x6105, 0x0002, 4, 3
	pea 0
	pea 300
	pea 0x0002
	pea 0x6100
	regsCall memmove, 0x6105, 0x0002, 4, 4
	pea 0
	pea 600
	pea 0x0003
	pea 0xff00
	regsCall memmove, 0xff40, 0x0003, 4, 5
	; memmove forward: short, one MVN, runs
	pea 0
	pea 20
	pea 0x0002
	pea 0x6105
	regsCall memmove, 0x6100, 0x0002, 4, 6
	pea 0
	pea 300
	pea 0x0002
	pea 0x6105
	regsCall memmove, 0x6100, 0x0002, 4, 7
	pea 0
	pea 600
	pea 0x0003
	pea 0xff40
	regsCall memmove, 0xff00, 0x0003, 4, 8
	; memset: short, one pass, over 64 KB
	pea 0
	pea 5
	pea 0x77
	regsCall memset, 0x6100, 0x0002, 3, 9
	pea 0
	pea 300
	pea 0x77
	regsCall memset, 0x6100, 0x0002, 3, 10
	pea 1
	pea 0x10
	pea 0x77
	regsCall memset, 0x0000, 0x0004, 3, 11
	pld
	plb
	lda REGS_OUT
	rtl