aboutsummaryrefslogtreecommitdiffstats
path: root/arch/m68k/math-emu/fp_decode.h
blob: 759679d9ab96610bec00ec8935063e25f2cfae4d (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
/*
 * fp_decode.h
 *
 * Copyright Roman Zippel, 1997.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, and the entire permission notice in its entirety,
 *    including the disclaimer of warranties.
 * 2. 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.
 * 3. The name of the author may not be used to endorse or promote
 *    products derived from this software without specific prior
 *    written permission.
 *
 * ALTERNATIVELY, this product may be distributed under the terms of
 * the GNU General Public License, in which case the provisions of the GPL are
 * required INSTEAD OF the above restrictions.  (This clause is
 * necessary due to a potential bad interaction between the GPL and
 * the restrictions contained in a BSD-style copyright.)
 *
 * THIS SOFTWARE IS PROVIDED ``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 AUTHOR 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.
 */

#ifndef _FP_DECODE_H
#define _FP_DECODE_H

/* These macros do the dirty work of the instr decoding, several variables
 * can be defined in the source file to modify the work of these macros,
 * currently the following variables are used:
 * ...
 * The register usage:
 * d0 - will contain source operand for data direct mode,
 *	otherwise scratch register
 * d1 - upper 16bit are reserved for caller
 *	lower 16bit may contain further arguments,
 *	is destroyed during decoding
 * d2 - contains first two instruction words,
 *	first word will be used for extension word
 * a0 - will point to source/dest operand for any indirect mode
 *	otherwise scratch register
 * a1 - scratch register
 * a2 - base addr to the task structure
 *
 * the current implementation doesn't check for every disallowed
 * addressing mode (e.g. pc relative modes as destination), as long
 * as it only means a new addressing mode, which should not appear
 * in a program and that doesn't crash the emulation, I think it's
 * not a problem to allow these modes.
 */

do_fmovem=0
do_fmovem_cr=0
do_no_pc_mode=0
do_fscc=0

| first decoding of the instr type
| this separates the conditional instr
.macro	fp_decode_cond_instr_type
	bfextu	%d2{#8,#2},%d0
	jmp	([0f:w,%pc,%d0*4])

	.align	4
0:
|	.long	"f<op>","fscc/fdbcc"
|	.long	"fbccw","fbccl"
.endm

| second decoding of the instr type
| this separates most move instr
.macro	fp_decode_move_instr_type
	bfextu	%d2{#16,#3},%d0
	jmp	([0f:w,%pc,%d0*4])

	.align	4
0:
|	.long	"f<op> fpx,fpx","invalid instr"
|	.long	"f<op> <ea>,fpx","fmove fpx,<ea>"
|	.long	"fmovem <ea>,fpcr","fmovem <ea>,fpx"
|	.long	"fmovem fpcr,<ea>","fmovem fpx,<ea>"
.endm

| extract the source specifier, specifies
| either source fp register or data format
.macro	fp_decode_sourcespec
	bfextu	%d2{#19,#3},%d0
.endm

| decode destination format for fmove reg,ea
.macro	fp_decode_dest_format
	bfextu	%d2{#19,#3},%d0
.endm

| decode source register for fmove reg,ea
.macro	fp_decode_src_reg
	bfextu	%d2{#22,#3},%d0
.endm

| extract the addressing mode
| it depends on the instr which of the modes is valid
.macro	fp_decode_addr_mode
	bfextu	%d2{#10,#3},%d0
	jmp	([0f:w,%pc,%d0*4])

	.align	4
0:
|	.long	"data register direct","addr register direct"
|	.long	"addr register indirect"
|	.long	"addr register indirect postincrement"
|	.long	"addr register indirect predecrement"
|	.long	"addr register + index16"
|	.long	"extension mode1","extension mode2"
.endm

| extract the register for the addressing mode
.macro	fp_decode_addr_reg
	bfextu	%d2{#13,#3},%d0
.endm

| decode the 8bit diplacement from the brief extension word
.macro	fp_decode_disp8
	move.b	%d2,%d0
	ext.w	%d0
.endm

| decode the index of the brief/full extension word
.macro	fp_decode_index
	bfextu	%d2{#17,#3},%d0		| get the register nr
	btst	#15,%d2			| test for data/addr register
	jne	1\@f
	printf	PDECODE,"d%d",1,%d0
	jsr	fp_get_data_reg
	jra	2\@f
1\@:	printf	PDECODE,"a%d",1,%d0
	jsr	fp_get_addr_reg
	move.l	%a0,%d0
2\@:
debug	lea	"'l'.w,%a0"
	btst	#11,%d2			| 16/32 bit size?
	jne	3\@f
debug	lea	"'w'.w,%a0"
	ext.l	%d0
3\@:	printf	PDECODE,":%c",1,%a0
	move.w	%d2,%d1			| scale factor
	rol.w	#7,%d1
	and.w	#3,%d1
debug	move.l	"%d1,-(%sp)"
debug	ext.l	"%d1"
	printf	PDECODE,":%d",1,%d1
debug	move.l	"(%sp)+,%d1"
	lsl.l	%d1,%d0
.endm

| decode the base displacement size
.macro	fp_decode_basedisp
	bfextu	%d2{#26,#2},%d0
	jmp	([0f:w,%pc,%d0*4])

	.align	4
0:
|	.long	"reserved","null displacement"
|	.long	"word displacement","long displacement"
.endm

.macro	fp_decode_outerdisp
	bfextu	%d2{#30,#2},%d0
	jmp	([0f:w,%pc,%d0*4])

	.align	4
0:
|	.long	"no memory indirect action/reserved","null outer displacement"
|	.long	"word outer displacement","long outer displacement"
.endm

| get the extension word and test for brief or full extension type
.macro	fp_get_test_extword label
	fp_get_instr_word %d2,fp_err_ua1
	btst	#8,%d2
	jne	\label
.endm


| test if %pc is the base register for the indirect addr mode
.macro	fp_test_basereg_d16	label
	btst	#20,%d2
	jeq	\label
.endm

| test if %pc is the base register for one of the extended modes
.macro	fp_test_basereg_ext	label
	btst	#19,%d2
	jeq	\label
.endm

.macro	fp_test_suppr_index label
	btst	#6,%d2
	jne	\label
.endm


| addressing mode: data register direct
.macro	fp_mode_data_direct
	fp_decode_addr_reg
	printf	PDECODE,"d%d",1,%d0
.endm

| addressing mode: address register indirect
.macro	fp_mode_addr_indirect
	fp_decode_addr_reg
	printf	PDECODE,"(a%d)",1,%d0
	jsr	fp_get_addr_reg
.endm

| adjust stack for byte moves from/to stack
.macro	fp_test_sp_byte_move
	.if	!do_fmovem
	.if	do_fscc
	move.w	#6,%d1
	.endif
	cmp.w	#7,%d0
	jne	1\@f
	.if	!do_fscc
	cmp.w	#6,%d1
	jne	1\@f
	.endif
	move.w	#4,%d1
1\@:
	.endif
.endm

| addressing mode: address register indirect with postincrement
.macro	fp_mode_addr_indirect_postinc
	fp_decode_addr_reg
	printf	PDECODE,"(a%d)+",1,%d0
	fp_test_sp_byte_move
	jsr	fp_get_addr_reg
	move.l	%a0,%a1			| save addr
	.if	do_fmovem
	lea	(%a0,%d1.w*4),%a0
	.if	!do_fmovem_cr
	lea	(%a0,%d1.w*8),%a0
	.endif
	.else
	add.w	(fp_datasize,%d1.w*2),%a0
	.endif
	jsr	fp_put_addr_reg
	move.l	%a1,%a0
.endm

| addressing mode: address register indirect with predecrement
.macro	fp_mode_addr_indirect_predec
	fp_decode_addr_reg
	printf	PDECODE,"-(a%d)",1,%d0
	fp_test_sp_byte_move
	jsr	fp_get_addr_reg
	.if	do_fmovem
	.if	!do_fmovem_cr
	lea	(-12,%a0),%a1		| setup to addr of 1st reg to move
	neg.w	%d1
	lea	(%a0,%d1.w*4),%a0
	add.w	%d1,%d1
	lea	(%a0,%d1.w*4),%a0
	jsr	fp_put_addr_reg
	move.l	%a1,%a0
	.else
	neg.w	%d1
	lea	(%a0,%d1.w*4),%a0
	jsr	fp_put_addr_reg
	.endif
	.else
	sub.w	(fp_datasize,%d1.w*2),%a0
	jsr	fp_put_addr_reg
	.endif
.endm

| addressing mode: address register/programm counter indirect
|		   with 16bit displacement
.macro	fp_mode_addr_indirect_disp16
	.if	!do_no_pc_mode
	fp_test_basereg_d16 1f
	printf	PDECODE,"pc"
	fp_get_pc %a0
	jra	2f
	.endif
1:	fp_decode_addr_reg
	printf	PDECODE,"a%d",1,%d0
	jsr	fp_get_addr_reg
2:	fp_get_instr_word %a1,fp_err_ua1
	printf	PDECODE,"@(%x)",1,%a1
	add.l	%a1,%a0
.endm

| perform preindex (if I/IS == 0xx and xx != 00)
.macro	fp_do_preindex
	moveq	#3,%d0
	and.w	%d2,%d0
	jeq	1f
	btst	#2,%d2
	jne	1f
	printf	PDECODE,")@("
	getuser.l (%a1),%a1,fp_err_ua1,%a1
debug	jra	"2f"
1:	printf	PDECODE,","
2:
.endm

| perform postindex (if I/IS == 1xx)
.macro	fp_do_postindex
	btst	#2,%d2
	jeq	1f
	printf	PDECODE,")@("
	getuser.l (%a1),%a1,fp_err_ua1,%a1
debug	jra	"2f"
1:	printf	PDECODE,","
2:
.endm

| all other indirect addressing modes will finally end up here
.macro	fp_mode_addr_indirect_extmode0
	.if	!do_no_pc_mode
	fp_test_basereg_ext 1f
	printf	PDECODE,"pc"
	fp_get_pc %a0
	jra	2f
	.endif
1:	fp_decode_addr_reg
	printf	PDECODE,"a%d",1,%d0
	jsr	fp_get_addr_reg
2:	move.l	%a0,%a1
	swap	%d2
	fp_get_test_extword 3f
	| addressing mode: address register/programm counter indirect
	|		   with index and 8bit displacement
	fp_decode_disp8
debug	ext.l	"%d0"
	printf	PDECODE,"@(%x,",1,%d0
	add.w	%d0,%a1
	fp_decode_index
	add.l	%d0,%a1
	printf	PDECODE,")"
	jra	9f
3:	| addressing mode: address register/programm counter memory indirect
	|		   with base and/or outer displacement
	btst	#7,%d2			| base register suppressed?
	jeq	1f
	printf	PDECODE,"!"
	sub.l	%a1,%a1
1:	printf	PDECODE,"@("
	fp_decode_basedisp

	.long	fp_ill,1f
	.long	2f,3f

#ifdef FPU_EMU_DEBUG
1:	printf	PDECODE,"0"		| null base displacement
	jra	1f
#endif
2:	fp_get_instr_word %a0,fp_err_ua1 | 16bit base displacement
	printf	PDECODE,"%x:w",1,%a0
	jra	4f
3:	fp_get_instr_long %a0,fp_err_ua1 | 32bit base displacement
	printf	PDECODE,"%x:l",1,%a0
4:	add.l	%a0,%a1
1:
	fp_do_postindex
	fp_test_suppr_index 1f
	fp_decode_index
	add.l	%d0,%a1
1:	fp_do_preindex

	fp_decode_outerdisp

	.long	5f,1f
	.long	2f,3f

#ifdef FPU_EMU_DEBUG
1:	printf	PDECODE,"0"		| null outer displacement
	jra	1f
#endif
2:	fp_get_instr_word %a0,fp_err_ua1 | 16bit outer displacement
	printf	PDECODE,"%x:w",1,%a0
	jra	4f
3:	fp_get_instr_long %a0,fp_err_ua1 | 32bit outer displacement
	printf	PDECODE,"%x:l",1,%a0
4:	add.l	%a0,%a1
1:
5:	printf	PDECODE,")"
9:	move.l	%a1,%a0
	swap	%d2
.endm

| get the absolute short address from user space
.macro	fp_mode_abs_short
	fp_get_instr_word %a0,fp_err_ua1
	printf	PDECODE,"%x.w",1,%a0
.endm

| get the absolute long address from user space
.macro	fp_mode_abs_long
	fp_get_instr_long %a0,fp_err_ua1
	printf	PDECODE,"%x.l",1,%a0
.endm

#endif /* _FP_DECODE_H */