[megadrive.git] / hexed / transfer.S

###############################################################################
#
# Copyright (c) 2011, Gražvydas Ignotas
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are met:
#     * Redistributions of source code must retain the above copyright
#       notice, this list of conditions and the following disclaimer.
#     * Redistributions in binary form must reproduce the above copyright
#       notice, this list of conditions and the following disclaimer in the
#       documentation and/or other materials provided with the distribution.
#     * Neither the name of the organization nor the
#       names of its contributors may be used to endorse or promote products
#       derived from this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND ANY
# EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
# WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
# DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE FOR ANY
# DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
# (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
# LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
# ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
# SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#
# Assemble with gas
#   --register-prefix-optional --bitwise-or
#

#include "transfer.h"

.text
.globl do_transfer


# receive 1 byte to d0
#  in: a1 - data port
#  trash: d1
.macro recv_one_byte is_last=0
	move.b		#0,(a1)		/* clear TH */

0: /*L_wait_tl_low*/
	move.b		(a1),d1
	btst.b		#4,d1
	bne		0b /*L_wait_tl_low*/

	move.b		#0x40,(a1)	/* set TH */
	and.b		#0x0f,d1

0: /*L_wait_tl_hi*/
	move.b		(a1),d0
	btst.b		#4,d0
	beq		0b /*L_wait_tl_hi*/

.if !\is_last
	move.b		#0,(a1)		/* clear TH - ready for next */
.endif
	lsl.b		#4,d0
	or.b		d1,d0
.endm

# send 1 byte in d0
#  in: a1 - data port
#  trash: d1,d2
.macro send_one_byte
	move.b		d0,d2
	and.b		#0x0f,d2

0: /*Lwait_tl_low:*/
	move.b		(a1),d1
	btst.b		#4,d1
	bne		0b /*Lwait_tl_low*/

	move.b		d2,(a1)		/* clears TH and writes data */

	move.b		d0,d2
	lsr.b		#4,d2
	bset.b		#6,d2		/* prepare TH */

0: /*wait_tl_hi*/
	move.b		(a1),d1
	btst.b		#4,d1
	beq		0b /*wait_tl_hi1*/

	move.b		d2,(a1)
.endm

recv_byte:
	moveq.l		#0,d0
	recv_one_byte 1
	rts

# receive address/size to d0 (3 bytes BE)
#  in: a1 - data port
#  trash: d1,d2
recv_ad:
	moveq.l		#0,d2
	bsr		recv_byte
	move.b		d0,d2
	bsr		recv_byte
	lsl.l		#8,d2
	move.b		d0,d2
	bsr		recv_byte
	lsl.l		#8,d2
	move.b		d0,d2
	move.l		d2,d0
	rts

send_byte:
	send_one_byte
	rts


do_transfer:
	lea		0xa10005,a1
	move.b		#0x40,(0xa1000b).l	/* ctrl - all inputs except TH */
	move.b		#0x00,(a1)

	bsr		recv_byte
	cmp.b		#CMD_PREFIX,d0
	bne		return

	bsr		recv_byte
	cmp.b		#CMD_FIRST,d0
	bcs		return
	cmp.b		#CMD_LAST+1,d0
	bcc		return
	sub.b		#CMD_FIRST,d0

	lsl.w		#2,d0
	lea		(jumptab,pc,d0),a0
	jmp		(a0)
jumptab:
	bra		pcc_transfer_recv	/* sent to us */
	bra		pcc_transfer_send	/* recv from us */
	bra		pcc_jump
	bra		pcc_io
	bra		pcc_test_code


/* receive data from PC */
pcc_transfer_recv:
	bsr		recv_ad
	move.l		d0,a0
	bsr		recv_ad
	move.l		d0,d3

tr_recv_loop:
	recv_one_byte
	move.b		d0,(a0)+
	subq.l		#1,d3
	bgt		tr_recv_loop
	bra		return


/* send data to PC */
pcc_transfer_send:
	bsr		recv_ad
	move.l		d0,a0
	bsr		recv_ad
	move.l		d0,d3

0: /*Lwait_tl_low: it should switch to rx mode before lowering tl */
	move.b		(a1),d0
	btst.b		#4,d0
	bne		0b /*Lwait_tl_low*/

	move.b		#0x4f,(0xa1000b).l
	move.b		#0x40,(a1)

tr_send_loop:
	move.b		(a0)+,d0
	send_one_byte
	subq.l		#1,d3
	bgt		tr_send_loop
	bra		return


/* call specified location */
pcc_jump:
	bsr		recv_ad
	move.l		d0,a0
	jsr		(a0)
	bra		return


/* do simple i/o commands */
pcc_io:
	moveq.l		#0,d4
	bsr		recv_byte
	move.b		d0,d4
	bsr		recv_byte
	lsl.l		#8,d4
	move.b		d0,d4

pcc_io_loop:
	move.b		#0x40,(0xa1000b).l	/* input mode */

	sub.w		#1,d4
	bmi		return

	bsr		recv_byte
	move.b		d0,d3			/* cmd */

	bsr		recv_ad
	move.l		d0,a2			/* addr */

	cmp.b		#IOSEQ_W32, d3
	beq		pcc_io_w32
	cmp.b		#IOSEQ_W16, d3
	beq		pcc_io_w16
	cmp.b		#IOSEQ_W8, d3
	bne		pcc_io_rx

pcc_io_w8:
	bsr		recv_byte
	move.b		d0,(a2)
	bra		pcc_io_loop

pcc_io_w16:
	bsr		recv_byte
	move.b		d0,d3
	bsr		recv_byte
	lsl.w		#8,d3
	move.b		d0,d3
	move.w		d3,(a2)
	bra		pcc_io_loop

pcc_io_w32:
	bsr		recv_byte
	move.b		d0,d3
	bsr		recv_byte
	lsl.w		#8,d3
	move.b		d0,d3
	bsr		recv_byte
	lsl.l		#8,d3
	move.b		d0,d3
	bsr		recv_byte
	lsl.l		#8,d3
	move.b		d0,d3
	move.l		d3,(a2)
	bra		pcc_io_loop

pcc_io_rx:
0: /*Lwait_tl_low:*/
	move.b		(a1),d0
	btst.b		#4,d0
	bne		0b /*Lwait_tl_low*/

	move.b		#0x4f,(0xa1000b).l
	move.b		#0x40,(a1)

	cmp.b		#IOSEQ_R32, d3
	beq		pcc_io_r32
	cmp.b		#IOSEQ_R16, d3
	beq		pcc_io_r16
	cmp.b		#IOSEQ_R8, d3
	bne		return

pcc_io_r8:
	move.b		(a2),d0
	bsr		send_byte
	bra		pcc_io_loop

pcc_io_r16:
	move.w		(a2),d3
	move.w		d3,d0
	lsr.w		#8,d0
	bsr		send_byte
	move.b		d3,d0
	bsr		send_byte
	bra		pcc_io_loop

pcc_io_r32:
	move.l		(a2),d3
	move.l		d3,d0
	swap		d0
	lsr.l		#8,d0
	bsr		send_byte
	move.l		d3,d0
	swap		d0
	bsr		send_byte
	move.w		d3,d0
	lsr.w		#8,d0
	bsr		send_byte
	move.b		d3,d0
	bsr		send_byte
	bra		pcc_io_loop


/* some random code */
pcc_test_code:
	bra		return


return:
	move.b		#0,(0xa1000b).l	/* all inputs */
	move.l		#0xffe000,a1
	move.l		d0,(a1)+	/* last state for debug */
	move.l		d1,(a1)+
	move.l		d2,(a1)+
	move.l		d3,(a1)+
	move.l		a0,(a1)+
	bra		return_to_main


# vim:filetype=asmM68k
Commit	Line	Data
8689c962	1	###############################################################################
	2	#
	3	# Copyright (c) 2011, Gražvydas Ignotas
	4	# All rights reserved.
	5	#
	6	# Redistribution and use in source and binary forms, with or without
	7	# modification, are permitted provided that the following conditions are met:
	8	# * Redistributions of source code must retain the above copyright
	9	# notice, this list of conditions and the following disclaimer.
	10	# * Redistributions in binary form must reproduce the above copyright
	11	# notice, this list of conditions and the following disclaimer in the
	12	# documentation and/or other materials provided with the distribution.
	13	# * Neither the name of the organization nor the
	14	# names of its contributors may be used to endorse or promote products
	15	# derived from this software without specific prior written permission.
	16	#
f28eaaad	17	# THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND ANY
8689c962	18	# EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
8689c962	19	# WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
f28eaaad	20	# DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE FOR ANY
8689c962	21	# DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
	22	# (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
	23	# LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
	24	# ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	25	# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
	26	# SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	27	#
	28	# Assemble with gas
	29	# --register-prefix-optional --bitwise-or
	30	#
	31
	32	#include "transfer.h"
	33
	34	.text
	35	.globl do_transfer
	36
	37
	38	# receive 1 byte to d0
	39	# in: a1 - data port
	40	# trash: d1
	41	.macro recv_one_byte is_last=0
	42	move.b #0,(a1) /* clear TH */
	43
	44	0: /L_wait_tl_low/
	45	move.b (a1),d1
	46	btst.b #4,d1
	47	bne 0b /L_wait_tl_low/
	48
	49	move.b #0x40,(a1) /* set TH */
	50	and.b #0x0f,d1
	51
	52	0: /L_wait_tl_hi/
	53	move.b (a1),d0
	54	btst.b #4,d0
	55	beq 0b /L_wait_tl_hi/
	56
	57	.if !\is_last
	58	move.b #0,(a1) /* clear TH - ready for next */
	59	.endif
	60	lsl.b #4,d0
	61	or.b d1,d0
	62	.endm
	63
	64	# send 1 byte in d0
	65	# in: a1 - data port
	66	# trash: d1,d2
	67	.macro send_one_byte
	68	move.b d0,d2
	69	and.b #0x0f,d2
	70
	71	0: /Lwait_tl_low:/
	72	move.b (a1),d1
	73	btst.b #4,d1
	74	bne 0b /Lwait_tl_low/
	75
	76	move.b d2,(a1) /* clears TH and writes data */
	77
	78	move.b d0,d2
	79	lsr.b #4,d2
	80	bset.b #6,d2 /* prepare TH */
	81
	82	0: /wait_tl_hi/
	83	move.b (a1),d1
	84	btst.b #4,d1
85	beq 0b /wait_tl_hi1/
86
87	move.b d2,(a1)
88	.endm
89
90	recv_byte:
272bd2ec	91	moveq.l #0,d0
8689c962	92	recv_one_byte 1
	93	rts
	94
	95	# receive address/size to d0 (3 bytes BE)
	96	# in: a1 - data port
	97	# trash: d1,d2
	98	recv_ad:
	99	moveq.l #0,d2
	100	bsr recv_byte
	101	move.b d0,d2
	102	bsr recv_byte
	103	lsl.l #8,d2
	104	move.b d0,d2
	105	bsr recv_byte
	106	lsl.l #8,d2
	107	move.b d0,d2
	108	move.l d2,d0
	109	rts
	110
93c5aa8a	111	send_byte:
	112	send_one_byte
	113	rts
	114
8689c962	115
	116	do_transfer:
	117	lea 0xa10005,a1
	118	move.b #0x40,(0xa1000b).l /* ctrl - all inputs except TH */
	119	move.b #0x00,(a1)
	120
	121	bsr recv_byte
	122	cmp.b #CMD_PREFIX,d0
	123	bne return
	124
	125	bsr recv_byte
272bd2ec	126	cmp.b #CMD_FIRST,d0
	127	bcs return
	128	cmp.b #CMD_LAST+1,d0
	129	bcc return
	130	sub.b #CMD_FIRST,d0
	131
	132	lsl.w #2,d0
	133	lea (jumptab,pc,d0),a0
	134	jmp (a0)
	135	jumptab:
	136	bra pcc_transfer_recv /* sent to us */
	137	bra pcc_transfer_send /* recv from us */
	138	bra pcc_jump
93c5aa8a	139	bra pcc_io
272bd2ec	140	bra pcc_test_code
	141
	142
93c5aa8a	143	/* receive data from PC */
272bd2ec	144	pcc_transfer_recv:
8689c962	145	bsr recv_ad
	146	move.l d0,a0
	147	bsr recv_ad
	148	move.l d0,d3
	149
	150	tr_recv_loop:
	151	recv_one_byte
	152	move.b d0,(a0)+
	153	subq.l #1,d3
272bd2ec	154	bgt tr_recv_loop
8689c962	155	bra return
8689c962	156
272bd2ec	157
93c5aa8a	158	/* send data to PC */
272bd2ec	159	pcc_transfer_send:
8689c962	160	bsr recv_ad
	161	move.l d0,a0
	162	bsr recv_ad
	163	move.l d0,d3
	164
93c5aa8a	165	0: /Lwait_tl_low: it should switch to rx mode before lowering tl /
8689c962	166	move.b (a1),d0
	167	btst.b #4,d0
	168	bne 0b /Lwait_tl_low/
	169
	170	move.b #0x4f,(0xa1000b).l
	171	move.b #0x40,(a1)
	172
	173	tr_send_loop:
	174	move.b (a0)+,d0
	175	send_one_byte
	176	subq.l #1,d3
272bd2ec	177	bgt tr_send_loop
	178	bra return
	179
	180
93c5aa8a	181	/* call specified location */
272bd2ec	182	pcc_jump:
	183	bsr recv_ad
	184	move.l d0,a0
93c5aa8a	185	jsr (a0)
	186	bra return
	187
	188
	189	/* do simple i/o commands */
	190	pcc_io:
	191	moveq.l #0,d4
	192	bsr recv_byte
	193	move.b d0,d4
	194	bsr recv_byte
	195	lsl.l #8,d4
	196	move.b d0,d4
272bd2ec	197
93c5aa8a	198	pcc_io_loop:
93c5aa8a	199	move.b #0x40,(0xa1000b).l /* input mode */
272bd2ec	200
93c5aa8a	201	sub.w #1,d4
	202	bmi return
	203
	204	bsr recv_byte
	205	move.b d0,d3 /* cmd */
	206
	207	bsr recv_ad
	208	move.l d0,a2 /* addr */
	209
	210	cmp.b #IOSEQ_W32, d3
	211	beq pcc_io_w32
	212	cmp.b #IOSEQ_W16, d3
	213	beq pcc_io_w16
	214	cmp.b #IOSEQ_W8, d3
	215	bne pcc_io_rx
	216
	217	pcc_io_w8:
	218	bsr recv_byte
	219	move.b d0,(a2)
	220	bra pcc_io_loop
	221
	222	pcc_io_w16:
	223	bsr recv_byte
	224	move.b d0,d3
	225	bsr recv_byte
	226	lsl.w #8,d3
	227	move.b d0,d3
	228	move.w d3,(a2)
	229	bra pcc_io_loop
	230
	231	pcc_io_w32:
	232	bsr recv_byte
	233	move.b d0,d3
	234	bsr recv_byte
	235	lsl.w #8,d3
	236	move.b d0,d3
	237	bsr recv_byte
	238	lsl.l #8,d3
	239	move.b d0,d3
	240	bsr recv_byte
	241	lsl.l #8,d3
	242	move.b d0,d3
	243	move.l d3,(a2)
	244	bra pcc_io_loop
	245
	246	pcc_io_rx:
	247	0: /Lwait_tl_low:/
	248	move.b (a1),d0
	249	btst.b #4,d0
	250	bne 0b /Lwait_tl_low/
	251
	252	move.b #0x4f,(0xa1000b).l
	253	move.b #0x40,(a1)
	254
	255	cmp.b #IOSEQ_R32, d3
	256	beq pcc_io_r32
	257	cmp.b #IOSEQ_R16, d3
	258	beq pcc_io_r16
	259	cmp.b #IOSEQ_R8, d3
	260	bne return
	261
	262	pcc_io_r8:
	263	move.b (a2),d0
	264	bsr send_byte
265	bra pcc_io_loop
266
267	pcc_io_r16:
268	move.w (a2),d3
269	move.w d3,d0
270	lsr.w #8,d0
271	bsr send_byte
272	move.b d3,d0
273	bsr send_byte
274	bra pcc_io_loop
275
276	pcc_io_r32:
277	move.l (a2),d3
278	move.l d3,d0
279	swap d0
280	lsr.l #8,d0
281	bsr send_byte
282	move.l d3,d0
283	swap d0
284	bsr send_byte
285	move.w d3,d0
286	lsr.w #8,d0
287	bsr send_byte
288	move.b d3,d0
289	bsr send_byte
290	bra pcc_io_loop
291
292
293	/* some random code */
272bd2ec	294	pcc_test_code:
8689c962	295	bra return
	296
	297
93c5aa8a	298
8689c962	299	return:
	300	move.b #0,(0xa1000b).l /* all inputs */
	301	move.l #0xffe000,a1
	302	move.l d0,(a1)+ /* last state for debug */
	303	move.l d1,(a1)+
	304	move.l d2,(a1)+
	305	move.l d3,(a1)+
	306	move.l a0,(a1)+
	307	bra return_to_main
	308
	309
	310	# vim:filetype=asmM68k