1 """Power ISA Decoder second stage
3 based on Anton Blanchard microwatt decode2.vhdl
5 Note: OP_TRAP is used for exceptions and interrupts (micro-code style) by
6 over-riding the internal opcode when an exception is needed.
9 from nmigen
import Module
, Elaboratable
, Signal
, Mux
, Const
, Cat
, Repl
, Record
10 from nmigen
.cli
import rtlil
11 from nmutil
.util
import sel
13 from soc
.regfile
.regfiles
import XERRegs
15 from nmutil
.picker
import PriorityPicker
16 from nmutil
.iocontrol
import RecordObject
17 from nmutil
.extend
import exts
19 from soc
.experiment
.mem_types
import LDSTException
21 from soc
.decoder
.power_svp64_prefix
import SVP64PrefixDecoder
22 from soc
.decoder
.power_svp64_extra
import SVP64CRExtra
, SVP64RegExtra
23 from soc
.decoder
.power_regspec_map
import regspec_decode_read
24 from soc
.decoder
.power_regspec_map
import regspec_decode_write
25 from soc
.decoder
.power_decoder
import create_pdecode
26 from soc
.decoder
.power_enums
import (MicrOp
, CryIn
, Function
,
28 LdstLen
, In1Sel
, In2Sel
, In3Sel
,
29 OutSel
, SPR
, RC
, LDSTMode
,
31 from soc
.decoder
.decode2execute1
import (Decode2ToExecute1Type
, Data
,
33 from soc
.sv
.svp64
import SVP64Rec
34 from soc
.consts
import (MSR
, SPEC
, EXTRA2
, EXTRA3
, SVP64P
, field
,
35 SPEC_SIZE
, SPECb
, SPEC_AUG_SIZE
, SVP64CROffs
)
37 from soc
.regfile
.regfiles
import FastRegs
38 from soc
.consts
import TT
39 from soc
.config
.state
import CoreState
40 from soc
.regfile
.util
import spr_to_fast
43 def decode_spr_num(spr
):
44 return Cat(spr
[5:10], spr
[0:5])
47 def instr_is_priv(m
, op
, insn
):
48 """determines if the instruction is privileged or not
51 is_priv_insn
= Signal(reset_less
=True)
53 with m
.Case(MicrOp
.OP_ATTN
, MicrOp
.OP_MFMSR
, MicrOp
.OP_MTMSRD
,
54 MicrOp
.OP_MTMSR
, MicrOp
.OP_RFID
):
55 comb
+= is_priv_insn
.eq(1)
56 with m
.Case(MicrOp
.OP_TLBIE
) : comb
+= is_priv_insn
.eq(1)
57 with m
.Case(MicrOp
.OP_MFSPR
, MicrOp
.OP_MTSPR
):
58 with m
.If(insn
[20]): # field XFX.spr[-1] i think
59 comb
+= is_priv_insn
.eq(1)
63 class SPRMap(Elaboratable
):
64 """SPRMap: maps POWER9 SPR numbers to internal enum values, fast and slow
68 self
.spr_i
= Signal(10, reset_less
=True)
69 self
.spr_o
= Data(SPR
, name
="spr_o")
70 self
.fast_o
= Data(3, name
="fast_o")
72 def elaborate(self
, platform
):
74 with m
.Switch(self
.spr_i
):
75 for i
, x
in enumerate(SPR
):
77 m
.d
.comb
+= self
.spr_o
.data
.eq(i
)
78 m
.d
.comb
+= self
.spr_o
.ok
.eq(1)
79 for x
, v
in spr_to_fast
.items():
81 m
.d
.comb
+= self
.fast_o
.data
.eq(v
)
82 m
.d
.comb
+= self
.fast_o
.ok
.eq(1)
86 class DecodeA(Elaboratable
):
87 """DecodeA from instruction
89 decodes register RA, implicit and explicit CSRs
92 def __init__(self
, dec
):
94 self
.sel_in
= Signal(In1Sel
, reset_less
=True)
95 self
.insn_in
= Signal(32, reset_less
=True)
96 self
.reg_out
= Data(5, name
="reg_a")
97 self
.spr_out
= Data(SPR
, "spr_a")
98 self
.fast_out
= Data(3, "fast_a")
100 def elaborate(self
, platform
):
105 m
.submodules
.sprmap
= sprmap
= SPRMap()
107 # select Register A field
108 ra
= Signal(5, reset_less
=True)
109 comb
+= ra
.eq(self
.dec
.RA
)
110 with m
.If((self
.sel_in
== In1Sel
.RA
) |
111 ((self
.sel_in
== In1Sel
.RA_OR_ZERO
) &
112 (ra
!= Const(0, 5)))):
113 comb
+= reg
.data
.eq(ra
)
116 # some Logic/ALU ops have RS as the 3rd arg, but no "RA".
117 # moved it to 1st position (in1_sel)... because
118 rs
= Signal(5, reset_less
=True)
119 comb
+= rs
.eq(self
.dec
.RS
)
120 with m
.If(self
.sel_in
== In1Sel
.RS
):
121 comb
+= reg
.data
.eq(rs
)
124 # decode Fast-SPR based on instruction type
125 with m
.Switch(op
.internal_op
):
127 # BC or BCREG: implicit register (CTR) NOTE: same in DecodeOut
128 with m
.Case(MicrOp
.OP_BC
):
129 with m
.If(~self
.dec
.BO
[2]): # 3.0B p38 BO2=0, use CTR reg
131 comb
+= self
.fast_out
.data
.eq(FastRegs
.CTR
)
132 comb
+= self
.fast_out
.ok
.eq(1)
133 with m
.Case(MicrOp
.OP_BCREG
):
134 xo9
= self
.dec
.FormXL
.XO
[9] # 3.0B p38 top bit of XO
135 xo5
= self
.dec
.FormXL
.XO
[5] # 3.0B p38
136 with m
.If(xo9
& ~xo5
):
138 comb
+= self
.fast_out
.data
.eq(FastRegs
.CTR
)
139 comb
+= self
.fast_out
.ok
.eq(1)
141 # MFSPR move from SPRs
142 with m
.Case(MicrOp
.OP_MFSPR
):
143 spr
= Signal(10, reset_less
=True)
144 comb
+= spr
.eq(decode_spr_num(self
.dec
.SPR
)) # from XFX
145 comb
+= sprmap
.spr_i
.eq(spr
)
146 comb
+= self
.spr_out
.eq(sprmap
.spr_o
)
147 comb
+= self
.fast_out
.eq(sprmap
.fast_o
)
152 class DecodeAImm(Elaboratable
):
153 """DecodeA immediate from instruction
155 decodes register RA, whether immediate-zero, implicit and
159 def __init__(self
, dec
):
161 self
.sel_in
= Signal(In1Sel
, reset_less
=True)
162 self
.immz_out
= Signal(reset_less
=True)
164 def elaborate(self
, platform
):
168 # zero immediate requested
169 ra
= Signal(5, reset_less
=True)
170 comb
+= ra
.eq(self
.dec
.RA
)
171 with m
.If((self
.sel_in
== In1Sel
.RA_OR_ZERO
) & (ra
== Const(0, 5))):
172 comb
+= self
.immz_out
.eq(1)
177 class DecodeB(Elaboratable
):
178 """DecodeB from instruction
180 decodes register RB, different forms of immediate (signed, unsigned),
181 and implicit SPRs. register B is basically "lane 2" into the CompUnits.
182 by industry-standard convention, "lane 2" is where fully-decoded
183 immediates are muxed in.
186 def __init__(self
, dec
):
188 self
.sel_in
= Signal(In2Sel
, reset_less
=True)
189 self
.insn_in
= Signal(32, reset_less
=True)
190 self
.reg_out
= Data(7, "reg_b")
191 self
.reg_isvec
= Signal(1, name
="reg_b_isvec") # TODO: in reg_out
192 self
.fast_out
= Data(3, "fast_b")
194 def elaborate(self
, platform
):
200 # select Register B field
201 with m
.Switch(self
.sel_in
):
202 with m
.Case(In2Sel
.RB
):
203 comb
+= reg
.data
.eq(self
.dec
.RB
)
205 with m
.Case(In2Sel
.RS
):
206 # for M-Form shiftrot
207 comb
+= reg
.data
.eq(self
.dec
.RS
)
210 # decode SPR2 based on instruction type
211 # BCREG implicitly uses LR or TAR for 2nd reg
212 # CTR however is already in fast_spr1 *not* 2.
213 with m
.If(op
.internal_op
== MicrOp
.OP_BCREG
):
214 xo9
= self
.dec
.FormXL
.XO
[9] # 3.0B p38 top bit of XO
215 xo5
= self
.dec
.FormXL
.XO
[5] # 3.0B p38
217 comb
+= self
.fast_out
.data
.eq(FastRegs
.LR
)
218 comb
+= self
.fast_out
.ok
.eq(1)
220 comb
+= self
.fast_out
.data
.eq(FastRegs
.TAR
)
221 comb
+= self
.fast_out
.ok
.eq(1)
226 class DecodeBImm(Elaboratable
):
227 """DecodeB immediate from instruction
229 def __init__(self
, dec
):
231 self
.sel_in
= Signal(In2Sel
, reset_less
=True)
232 self
.imm_out
= Data(64, "imm_b")
234 def elaborate(self
, platform
):
238 # select Register B Immediate
239 with m
.Switch(self
.sel_in
):
240 with m
.Case(In2Sel
.CONST_UI
): # unsigned
241 comb
+= self
.imm_out
.data
.eq(self
.dec
.UI
)
242 comb
+= self
.imm_out
.ok
.eq(1)
243 with m
.Case(In2Sel
.CONST_SI
): # sign-extended 16-bit
244 si
= Signal(16, reset_less
=True)
245 comb
+= si
.eq(self
.dec
.SI
)
246 comb
+= self
.imm_out
.data
.eq(exts(si
, 16, 64))
247 comb
+= self
.imm_out
.ok
.eq(1)
248 with m
.Case(In2Sel
.CONST_SI_HI
): # sign-extended 16+16=32 bit
249 si_hi
= Signal(32, reset_less
=True)
250 comb
+= si_hi
.eq(self
.dec
.SI
<< 16)
251 comb
+= self
.imm_out
.data
.eq(exts(si_hi
, 32, 64))
252 comb
+= self
.imm_out
.ok
.eq(1)
253 with m
.Case(In2Sel
.CONST_UI_HI
): # unsigned
254 ui
= Signal(16, reset_less
=True)
255 comb
+= ui
.eq(self
.dec
.UI
)
256 comb
+= self
.imm_out
.data
.eq(ui
<< 16)
257 comb
+= self
.imm_out
.ok
.eq(1)
258 with m
.Case(In2Sel
.CONST_LI
): # sign-extend 24+2=26 bit
259 li
= Signal(26, reset_less
=True)
260 comb
+= li
.eq(self
.dec
.LI
<< 2)
261 comb
+= self
.imm_out
.data
.eq(exts(li
, 26, 64))
262 comb
+= self
.imm_out
.ok
.eq(1)
263 with m
.Case(In2Sel
.CONST_BD
): # sign-extend (14+2)=16 bit
264 bd
= Signal(16, reset_less
=True)
265 comb
+= bd
.eq(self
.dec
.BD
<< 2)
266 comb
+= self
.imm_out
.data
.eq(exts(bd
, 16, 64))
267 comb
+= self
.imm_out
.ok
.eq(1)
268 with m
.Case(In2Sel
.CONST_DS
): # sign-extended (14+2=16) bit
269 ds
= Signal(16, reset_less
=True)
270 comb
+= ds
.eq(self
.dec
.DS
<< 2)
271 comb
+= self
.imm_out
.data
.eq(exts(ds
, 16, 64))
272 comb
+= self
.imm_out
.ok
.eq(1)
273 with m
.Case(In2Sel
.CONST_M1
): # signed (-1)
274 comb
+= self
.imm_out
.data
.eq(~
Const(0, 64)) # all 1s
275 comb
+= self
.imm_out
.ok
.eq(1)
276 with m
.Case(In2Sel
.CONST_SH
): # unsigned - for shift
277 comb
+= self
.imm_out
.data
.eq(self
.dec
.sh
)
278 comb
+= self
.imm_out
.ok
.eq(1)
279 with m
.Case(In2Sel
.CONST_SH32
): # unsigned - for shift
280 comb
+= self
.imm_out
.data
.eq(self
.dec
.SH32
)
281 comb
+= self
.imm_out
.ok
.eq(1)
286 class DecodeC(Elaboratable
):
287 """DecodeC from instruction
289 decodes register RC. this is "lane 3" into some CompUnits (not many)
292 def __init__(self
, dec
):
294 self
.sel_in
= Signal(In3Sel
, reset_less
=True)
295 self
.insn_in
= Signal(32, reset_less
=True)
296 self
.reg_out
= Data(5, "reg_c")
298 def elaborate(self
, platform
):
304 # select Register C field
305 with m
.Switch(self
.sel_in
):
306 with m
.Case(In3Sel
.RB
):
307 # for M-Form shiftrot
308 comb
+= reg
.data
.eq(self
.dec
.RB
)
310 with m
.Case(In3Sel
.RS
):
311 comb
+= reg
.data
.eq(self
.dec
.RS
)
317 class DecodeOut(Elaboratable
):
318 """DecodeOut from instruction
320 decodes output register RA, RT or SPR
323 def __init__(self
, dec
):
325 self
.sel_in
= Signal(OutSel
, reset_less
=True)
326 self
.insn_in
= Signal(32, reset_less
=True)
327 self
.reg_out
= Data(5, "reg_o")
328 self
.spr_out
= Data(SPR
, "spr_o")
329 self
.fast_out
= Data(3, "fast_o")
331 def elaborate(self
, platform
):
334 m
.submodules
.sprmap
= sprmap
= SPRMap()
338 # select Register out field
339 with m
.Switch(self
.sel_in
):
340 with m
.Case(OutSel
.RT
):
341 comb
+= reg
.data
.eq(self
.dec
.RT
)
343 with m
.Case(OutSel
.RA
):
344 comb
+= reg
.data
.eq(self
.dec
.RA
)
346 with m
.Case(OutSel
.SPR
):
347 spr
= Signal(10, reset_less
=True)
348 comb
+= spr
.eq(decode_spr_num(self
.dec
.SPR
)) # from XFX
349 # MFSPR move to SPRs - needs mapping
350 with m
.If(op
.internal_op
== MicrOp
.OP_MTSPR
):
351 comb
+= sprmap
.spr_i
.eq(spr
)
352 comb
+= self
.spr_out
.eq(sprmap
.spr_o
)
353 comb
+= self
.fast_out
.eq(sprmap
.fast_o
)
356 with m
.Switch(op
.internal_op
):
358 # BC or BCREG: implicit register (CTR) NOTE: same in DecodeA
359 with m
.Case(MicrOp
.OP_BC
, MicrOp
.OP_BCREG
):
360 with m
.If(~self
.dec
.BO
[2]): # 3.0B p38 BO2=0, use CTR reg
362 comb
+= self
.fast_out
.data
.eq(FastRegs
.CTR
)
363 comb
+= self
.fast_out
.ok
.eq(1)
365 # RFID 1st spr (fast)
366 with m
.Case(MicrOp
.OP_RFID
):
367 comb
+= self
.fast_out
.data
.eq(FastRegs
.SRR0
) # constant: SRR0
368 comb
+= self
.fast_out
.ok
.eq(1)
373 class DecodeOut2(Elaboratable
):
374 """DecodeOut2 from instruction
376 decodes output registers (2nd one). note that RA is *implicit* below,
377 which now causes problems with SVP64
379 TODO: SVP64 is a little more complex, here. svp64 allows extending
380 by one more destination by having one more EXTRA field. RA-as-src
381 is not the same as RA-as-dest. limited in that it's the same first
382 5 bits (from the v3.0B opcode), but still kinda cool. mostly used
383 for operations that have src-as-dest: mostly this is LD/ST-with-update
384 but there are others.
387 def __init__(self
, dec
):
389 self
.sel_in
= Signal(OutSel
, reset_less
=True)
390 self
.lk
= Signal(reset_less
=True)
391 self
.insn_in
= Signal(32, reset_less
=True)
392 self
.reg_out
= Data(5, "reg_o2")
393 self
.fast_out
= Data(3, "fast_o2")
395 def elaborate(self
, platform
):
399 #m.submodules.svdec = svdec = SVP64RegExtra()
401 # get the 5-bit reg data before svp64-munging it into 7-bit plus isvec
402 #reg = Signal(5, reset_less=True)
404 if hasattr(self
.dec
.op
, "upd"):
405 # update mode LD/ST uses read-reg A also as an output
406 with m
.If(self
.dec
.op
.upd
== LDSTMode
.update
):
407 comb
+= self
.reg_out
.data
.eq(self
.dec
.RA
)
408 comb
+= self
.reg_out
.ok
.eq(1)
410 # B, BC or BCREG: potential implicit register (LR) output
411 # these give bl, bcl, bclrl, etc.
412 with m
.Switch(op
.internal_op
):
414 # BC* implicit register (LR)
415 with m
.Case(MicrOp
.OP_BC
, MicrOp
.OP_B
, MicrOp
.OP_BCREG
):
416 with m
.If(self
.lk
): # "link" mode
417 comb
+= self
.fast_out
.data
.eq(FastRegs
.LR
) # constant: LR
418 comb
+= self
.fast_out
.ok
.eq(1)
420 # RFID 2nd spr (fast)
421 with m
.Case(MicrOp
.OP_RFID
):
422 comb
+= self
.fast_out
.data
.eq(FastRegs
.SRR1
) # constant: SRR1
423 comb
+= self
.fast_out
.ok
.eq(1)
428 class DecodeRC(Elaboratable
):
429 """DecodeRc from instruction
431 decodes Record bit Rc
434 def __init__(self
, dec
):
436 self
.sel_in
= Signal(RC
, reset_less
=True)
437 self
.insn_in
= Signal(32, reset_less
=True)
438 self
.rc_out
= Data(1, "rc")
440 def elaborate(self
, platform
):
444 # select Record bit out field
445 with m
.Switch(self
.sel_in
):
447 comb
+= self
.rc_out
.data
.eq(self
.dec
.Rc
)
448 comb
+= self
.rc_out
.ok
.eq(1)
450 comb
+= self
.rc_out
.data
.eq(1)
451 comb
+= self
.rc_out
.ok
.eq(1)
452 with m
.Case(RC
.NONE
):
453 comb
+= self
.rc_out
.data
.eq(0)
454 comb
+= self
.rc_out
.ok
.eq(1)
459 class DecodeOE(Elaboratable
):
460 """DecodeOE from instruction
462 decodes OE field: uses RC decode detection which might not be good
464 -- For now, use "rc" in the decode table to decide whether oe exists.
465 -- This is not entirely correct architecturally: For mulhd and
466 -- mulhdu, the OE field is reserved. It remains to be seen what an
467 -- actual POWER9 does if we set it on those instructions, for now we
468 -- test that further down when assigning to the multiplier oe input.
471 def __init__(self
, dec
):
473 self
.sel_in
= Signal(RC
, reset_less
=True)
474 self
.insn_in
= Signal(32, reset_less
=True)
475 self
.oe_out
= Data(1, "oe")
477 def elaborate(self
, platform
):
482 with m
.Switch(op
.internal_op
):
484 # mulhw, mulhwu, mulhd, mulhdu - these *ignore* OE
486 # XXX ARGH! ignoring OE causes incompatibility with microwatt
487 # http://lists.libre-soc.org/pipermail/libre-soc-dev/2020-August/000302.html
488 with m
.Case(MicrOp
.OP_MUL_H64
, MicrOp
.OP_MUL_H32
,
489 MicrOp
.OP_EXTS
, MicrOp
.OP_CNTZ
,
490 MicrOp
.OP_SHL
, MicrOp
.OP_SHR
, MicrOp
.OP_RLC
,
491 MicrOp
.OP_LOAD
, MicrOp
.OP_STORE
,
492 MicrOp
.OP_RLCL
, MicrOp
.OP_RLCR
,
496 # all other ops decode OE field
498 # select OE bit out field
499 with m
.Switch(self
.sel_in
):
501 comb
+= self
.oe_out
.data
.eq(self
.dec
.OE
)
502 comb
+= self
.oe_out
.ok
.eq(1)
507 class DecodeCRIn(Elaboratable
):
508 """Decodes input CR from instruction
510 CR indices - insn fields - (not the data *in* the CR) require only 3
511 bits because they refer to CR0-CR7
514 def __init__(self
, dec
):
516 self
.sel_in
= Signal(CRInSel
, reset_less
=True)
517 self
.insn_in
= Signal(32, reset_less
=True)
518 self
.cr_bitfield
= Data(3, "cr_bitfield")
519 self
.cr_bitfield_b
= Data(3, "cr_bitfield_b")
520 self
.cr_bitfield_o
= Data(3, "cr_bitfield_o")
521 self
.whole_reg
= Data(8, "cr_fxm")
522 self
.sv_override
= Signal(2, reset_less
=True) # do not do EXTRA spec
524 def elaborate(self
, platform
):
528 m
.submodules
.ppick
= ppick
= PriorityPicker(8, reverse_i
=True,
531 # zero-initialisation
532 comb
+= self
.cr_bitfield
.ok
.eq(0)
533 comb
+= self
.cr_bitfield_b
.ok
.eq(0)
534 comb
+= self
.cr_bitfield_o
.ok
.eq(0)
535 comb
+= self
.whole_reg
.ok
.eq(0)
536 comb
+= self
.sv_override
.eq(0)
538 # select the relevant CR bitfields
539 with m
.Switch(self
.sel_in
):
540 with m
.Case(CRInSel
.NONE
):
541 pass # No bitfield activated
542 with m
.Case(CRInSel
.CR0
):
543 comb
+= self
.cr_bitfield
.data
.eq(0) # CR0 (MSB0 numbering)
544 comb
+= self
.cr_bitfield
.ok
.eq(1)
545 comb
+= self
.sv_override
.eq(1)
546 with m
.Case(CRInSel
.CR1
):
547 comb
+= self
.cr_bitfield
.data
.eq(1) # CR1 (MSB0 numbering)
548 comb
+= self
.cr_bitfield
.ok
.eq(1)
549 comb
+= self
.sv_override
.eq(2)
550 with m
.Case(CRInSel
.BI
):
551 comb
+= self
.cr_bitfield
.data
.eq(self
.dec
.BI
[2:5])
552 comb
+= self
.cr_bitfield
.ok
.eq(1)
553 with m
.Case(CRInSel
.BFA
):
554 comb
+= self
.cr_bitfield
.data
.eq(self
.dec
.FormX
.BFA
)
555 comb
+= self
.cr_bitfield
.ok
.eq(1)
556 with m
.Case(CRInSel
.BA_BB
):
557 comb
+= self
.cr_bitfield
.data
.eq(self
.dec
.BA
[2:5])
558 comb
+= self
.cr_bitfield
.ok
.eq(1)
559 comb
+= self
.cr_bitfield_b
.data
.eq(self
.dec
.BB
[2:5])
560 comb
+= self
.cr_bitfield_b
.ok
.eq(1)
561 comb
+= self
.cr_bitfield_o
.data
.eq(self
.dec
.BT
[2:5])
562 comb
+= self
.cr_bitfield_o
.ok
.eq(1)
563 with m
.Case(CRInSel
.BC
):
564 comb
+= self
.cr_bitfield
.data
.eq(self
.dec
.BC
[2:5])
565 comb
+= self
.cr_bitfield
.ok
.eq(1)
566 with m
.Case(CRInSel
.WHOLE_REG
):
567 comb
+= self
.whole_reg
.ok
.eq(1)
568 move_one
= Signal(reset_less
=True)
569 comb
+= move_one
.eq(self
.insn_in
[20]) # MSB0 bit 11
570 with m
.If((op
.internal_op
== MicrOp
.OP_MFCR
) & move_one
):
571 # must one-hot the FXM field
572 comb
+= ppick
.i
.eq(self
.dec
.FXM
)
573 comb
+= self
.whole_reg
.data
.eq(ppick
.o
)
575 # otherwise use all of it
576 comb
+= self
.whole_reg
.data
.eq(0xff)
581 class DecodeCROut(Elaboratable
):
582 """Decodes input CR from instruction
584 CR indices - insn fields - (not the data *in* the CR) require only 3
585 bits because they refer to CR0-CR7
588 def __init__(self
, dec
):
590 self
.rc_in
= Signal(reset_less
=True)
591 self
.sel_in
= Signal(CROutSel
, reset_less
=True)
592 self
.insn_in
= Signal(32, reset_less
=True)
593 self
.cr_bitfield
= Data(3, "cr_bitfield")
594 self
.whole_reg
= Data(8, "cr_fxm")
595 self
.sv_override
= Signal(2, reset_less
=True) # do not do EXTRA spec
597 def elaborate(self
, platform
):
601 m
.submodules
.ppick
= ppick
= PriorityPicker(8, reverse_i
=True,
604 comb
+= self
.cr_bitfield
.ok
.eq(0)
605 comb
+= self
.whole_reg
.ok
.eq(0)
606 comb
+= self
.sv_override
.eq(0)
608 # please note these MUST match (setting of cr_bitfield.ok) exactly
609 # with write_cr0 below in PowerDecoder2. the reason it's separated
610 # is to avoid having duplicate copies of DecodeCROut in multiple
611 # PowerDecoderSubsets. register decoding should be a one-off in
612 # PowerDecoder2. see https://bugs.libre-soc.org/show_bug.cgi?id=606
614 with m
.Switch(self
.sel_in
):
615 with m
.Case(CROutSel
.NONE
):
616 pass # No bitfield activated
617 with m
.Case(CROutSel
.CR0
):
618 comb
+= self
.cr_bitfield
.data
.eq(0) # CR0 (MSB0 numbering)
619 comb
+= self
.cr_bitfield
.ok
.eq(self
.rc_in
) # only when RC=1
620 comb
+= self
.sv_override
.eq(1)
621 with m
.Case(CROutSel
.CR1
):
622 comb
+= self
.cr_bitfield
.data
.eq(1) # CR1 (MSB0 numbering)
623 comb
+= self
.cr_bitfield
.ok
.eq(self
.rc_in
) # only when RC=1
624 comb
+= self
.sv_override
.eq(2)
625 with m
.Case(CROutSel
.BF
):
626 comb
+= self
.cr_bitfield
.data
.eq(self
.dec
.FormX
.BF
)
627 comb
+= self
.cr_bitfield
.ok
.eq(1)
628 with m
.Case(CROutSel
.BT
):
629 comb
+= self
.cr_bitfield
.data
.eq(self
.dec
.FormXL
.BT
[2:5])
630 comb
+= self
.cr_bitfield
.ok
.eq(1)
631 with m
.Case(CROutSel
.WHOLE_REG
):
632 comb
+= self
.whole_reg
.ok
.eq(1)
633 move_one
= Signal(reset_less
=True)
634 comb
+= move_one
.eq(self
.insn_in
[20])
635 with m
.If((op
.internal_op
== MicrOp
.OP_MTCRF
)):
637 # must one-hot the FXM field
638 comb
+= ppick
.i
.eq(self
.dec
.FXM
)
639 with m
.If(ppick
.en_o
):
640 comb
+= self
.whole_reg
.data
.eq(ppick
.o
)
642 comb
+= self
.whole_reg
.data
.eq(0b00000001) # CR7
644 comb
+= self
.whole_reg
.data
.eq(self
.dec
.FXM
)
646 # otherwise use all of it
647 comb
+= self
.whole_reg
.data
.eq(0xff)
651 # dictionary of Input Record field names that, if they exist,
652 # will need a corresponding CSV Decoder file column (actually, PowerOp)
653 # to be decoded (this includes the single bit names)
654 record_names
= {'insn_type': 'internal_op',
655 'fn_unit': 'function_unit',
659 'imm_data': 'in2_sel',
660 'invert_in': 'inv_a',
661 'invert_out': 'inv_out',
664 'output_carry': 'cry_out',
665 'input_carry': 'cry_in',
666 'is_32bit': 'is_32b',
669 'data_len': 'ldst_len',
670 'byte_reverse': 'br',
671 'sign_extend': 'sgn_ext',
676 class PowerDecodeSubset(Elaboratable
):
677 """PowerDecodeSubset: dynamic subset decoder
679 only fields actually requested are copied over. hence, "subset" (duh).
681 def __init__(self
, dec
, opkls
=None, fn_name
=None, final
=False, state
=None):
683 self
.sv_rm
= SVP64Rec(name
="dec_svp64") # SVP64 RM field
686 self
.fn_name
= fn_name
688 opkls
= Decode2ToOperand
689 self
.do
= opkls(fn_name
)
690 col_subset
= self
.get_col_subset(self
.do
)
692 # only needed for "main" PowerDecode2
694 self
.e
= Decode2ToExecute1Type(name
=self
.fn_name
, do
=self
.do
)
696 # create decoder if one not already given
698 dec
= create_pdecode(name
=fn_name
, col_subset
=col_subset
,
699 row_subset
=self
.rowsubsetfn
)
702 # state information needed by the Decoder
704 state
= CoreState("dec2")
707 def get_col_subset(self
, do
):
708 subset
= { 'cr_in', 'cr_out', 'rc_sel'} # needed, non-optional
709 for k
, v
in record_names
.items():
712 print ("get_col_subset", self
.fn_name
, do
.fields
, subset
)
715 def rowsubsetfn(self
, opcode
, row
):
716 return row
['unit'] == self
.fn_name
719 return self
.dec
.ports() + self
.e
.ports() + self
.sv_rm
.ports()
721 def needs_field(self
, field
, op_field
):
726 return hasattr(do
, field
) and self
.op_get(op_field
) is not None
728 def do_copy(self
, field
, val
, final
=False):
729 if final
or self
.final
:
733 if hasattr(do
, field
) and val
is not None:
734 return getattr(do
, field
).eq(val
)
737 def op_get(self
, op_field
):
738 return getattr(self
.dec
.op
, op_field
, None)
740 def elaborate(self
, platform
):
744 op
, do
= self
.dec
.op
, self
.do
745 msr
, cia
= state
.msr
, state
.pc
746 # fill in for a normal instruction (not an exception)
747 # copy over if non-exception, non-privileged etc. is detected
749 if self
.fn_name
is None:
752 name
= self
.fn_name
+ "tmp"
753 self
.e_tmp
= Decode2ToExecute1Type(name
=name
, opkls
=self
.opkls
)
755 # set up submodule decoders
756 m
.submodules
.dec
= self
.dec
757 m
.submodules
.dec_rc
= self
.dec_rc
= dec_rc
= DecodeRC(self
.dec
)
758 m
.submodules
.dec_oe
= dec_oe
= DecodeOE(self
.dec
)
760 # copy instruction through...
761 for i
in [do
.insn
, dec_rc
.insn_in
, dec_oe
.insn_in
, ]:
762 comb
+= i
.eq(self
.dec
.opcode_in
)
764 # ...and subdecoders' input fields
765 comb
+= dec_rc
.sel_in
.eq(op
.rc_sel
)
766 comb
+= dec_oe
.sel_in
.eq(op
.rc_sel
) # XXX should be OE sel
769 comb
+= self
.do_copy("msr", msr
)
770 comb
+= self
.do_copy("cia", cia
)
772 # set up instruction type
773 # no op: defaults to OP_ILLEGAL
774 if self
.fn_name
=="MMU":
775 # mmu is special case: needs SPR opcode as well
776 mmu0
= self
.mmu0_spr_dec
777 with m
.If(((mmu0
.dec
.op
.internal_op
== MicrOp
.OP_MTSPR
) |
778 (mmu0
.dec
.op
.internal_op
== MicrOp
.OP_MFSPR
))):
779 comb
+= self
.do_copy("insn_type", mmu0
.op_get("internal_op"))
781 comb
+= self
.do_copy("insn_type", self
.op_get("internal_op"))
783 comb
+= self
.do_copy("insn_type", self
.op_get("internal_op"))
785 # function unit for decoded instruction: requires minor redirect
787 fn
= self
.op_get("function_unit")
788 spr
= Signal(10, reset_less
=True)
789 comb
+= spr
.eq(decode_spr_num(self
.dec
.SPR
)) # from XFX
791 # Microwatt doesn't implement the partition table
792 # instead has PRTBL(SVSRR0) register (SPR) to point to process table
793 with m
.If(((self
.dec
.op
.internal_op
== MicrOp
.OP_MTSPR
) |
794 (self
.dec
.op
.internal_op
== MicrOp
.OP_MFSPR
)) &
795 ((spr
== SPR
.DSISR
.value
) |
(spr
== SPR
.DAR
.value
) |
796 (spr
==SPR
.SVSRR0
.value
) |
(spr
==SPR
.PIDR
.value
))):
797 comb
+= self
.do_copy("fn_unit", Function
.MMU
)
799 comb
+= self
.do_copy("fn_unit",fn
)
802 if self
.needs_field("zero_a", "in1_sel"):
803 m
.submodules
.dec_ai
= dec_ai
= DecodeAImm(self
.dec
)
804 comb
+= dec_ai
.sel_in
.eq(op
.in1_sel
)
805 comb
+= self
.do_copy("zero_a", dec_ai
.immz_out
) # RA==0 detected
806 if self
.needs_field("imm_data", "in2_sel"):
807 m
.submodules
.dec_bi
= dec_bi
= DecodeBImm(self
.dec
)
808 comb
+= dec_bi
.sel_in
.eq(op
.in2_sel
)
809 comb
+= self
.do_copy("imm_data", dec_bi
.imm_out
) # imm in RB
812 comb
+= self
.do_copy("rc", dec_rc
.rc_out
)
813 comb
+= self
.do_copy("oe", dec_oe
.oe_out
)
815 # CR in/out - note: these MUST match with what happens in
817 rc_out
= self
.dec_rc
.rc_out
.data
818 with m
.Switch(op
.cr_out
):
819 with m
.Case(CROutSel
.CR0
, CROutSel
.CR1
):
820 comb
+= self
.do_copy("write_cr0", rc_out
) # only when RC=1
821 with m
.Case(CROutSel
.BF
, CROutSel
.BT
):
822 comb
+= self
.do_copy("write_cr0", 1)
824 comb
+= self
.do_copy("input_cr", self
.op_get("cr_in")) # CR in
825 comb
+= self
.do_copy("output_cr", self
.op_get("cr_out")) # CR out
827 # decoded/selected instruction flags
828 comb
+= self
.do_copy("data_len", self
.op_get("ldst_len"))
829 comb
+= self
.do_copy("invert_in", self
.op_get("inv_a"))
830 comb
+= self
.do_copy("invert_out", self
.op_get("inv_out"))
831 comb
+= self
.do_copy("input_carry", self
.op_get("cry_in"))
832 comb
+= self
.do_copy("output_carry", self
.op_get("cry_out"))
833 comb
+= self
.do_copy("is_32bit", self
.op_get("is_32b"))
834 comb
+= self
.do_copy("is_signed", self
.op_get("sgn"))
835 lk
= self
.op_get("lk")
838 comb
+= self
.do_copy("lk", self
.dec
.LK
) # XXX TODO: accessor
840 comb
+= self
.do_copy("byte_reverse", self
.op_get("br"))
841 comb
+= self
.do_copy("sign_extend", self
.op_get("sgn_ext"))
842 comb
+= self
.do_copy("ldst_mode", self
.op_get("upd")) # LD/ST mode
847 class PowerDecode2(PowerDecodeSubset
):
848 """PowerDecode2: the main instruction decoder.
850 whilst PowerDecode is responsible for decoding the actual opcode, this
851 module encapsulates further specialist, sparse information and
852 expansion of fields that is inconvenient to have in the CSV files.
853 for example: the encoding of the immediates, which are detected
854 and expanded out to their full value from an annotated (enum)
857 implicit register usage is also set up, here. for example: OP_BC
858 requires implicitly reading CTR, OP_RFID requires implicitly writing
861 in addition, PowerDecoder2 is responsible for detecting whether
862 instructions are illegal (or privileged) or not, and instead of
863 just leaving at that, *replacing* the instruction to execute with
864 a suitable alternative (trap).
866 LDSTExceptions are done the cycle _after_ they're detected (after
867 they come out of LDSTCompUnit). basically despite the instruction
868 being decoded, the results of the decode are completely ignored
869 and "exception.happened" used to set the "actual" instruction to
870 "OP_TRAP". the LDSTException data structure gets filled in,
871 in the CompTrapOpSubset and that's what it fills in SRR.
873 to make this work, TestIssuer must notice "exception.happened"
874 after the (failed) LD/ST and copies the LDSTException info from
875 the output, into here (PowerDecoder2). without incrementing PC.
878 def __init__(self
, dec
, opkls
=None, fn_name
=None, final
=False, state
=None):
879 super().__init
__(dec
, opkls
, fn_name
, final
, state
)
880 self
.exc
= LDSTException("dec2_exc")
882 self
.cr_out_isvec
= Signal(1, name
="cr_out_isvec")
883 self
.cr_in_isvec
= Signal(1, name
="cr_in_isvec")
884 self
.cr_in_b_isvec
= Signal(1, name
="cr_in_b_isvec")
885 self
.cr_in_o_isvec
= Signal(1, name
="cr_in_o_isvec")
886 self
.in1_isvec
= Signal(1, name
="reg_a_isvec")
887 self
.in2_isvec
= Signal(1, name
="reg_b_isvec")
888 self
.in3_isvec
= Signal(1, name
="reg_c_isvec")
889 self
.o_isvec
= Signal(1, name
="reg_o_isvec")
890 self
.o2_isvec
= Signal(1, name
="reg_o2_isvec")
891 self
.no_in_vec
= Signal(1, name
="no_in_vec") # no inputs are vectors
892 self
.no_out_vec
= Signal(1, name
="no_out_vec") # no outputs are vectors
894 def get_col_subset(self
, opkls
):
895 subset
= super().get_col_subset(opkls
)
896 subset
.add("asmcode")
897 subset
.add("in1_sel")
898 subset
.add("in2_sel")
899 subset
.add("in3_sel")
900 subset
.add("out_sel")
905 subset
.add("sv_cr_in")
906 subset
.add("sv_cr_out")
907 subset
.add("SV_Etype")
908 subset
.add("SV_Ptype")
910 subset
.add("internal_op")
914 def elaborate(self
, platform
):
915 m
= super().elaborate(platform
)
918 e_out
, op
, do_out
= self
.e
, self
.dec
.op
, self
.e
.do
919 dec_spr
, msr
, cia
, ext_irq
= state
.dec
, state
.msr
, state
.pc
, state
.eint
920 rc_out
= self
.dec_rc
.rc_out
.data
924 # fill in for a normal instruction (not an exception)
925 # copy over if non-exception, non-privileged etc. is detected
927 # set up submodule decoders
928 m
.submodules
.dec_a
= dec_a
= DecodeA(self
.dec
)
929 m
.submodules
.dec_b
= dec_b
= DecodeB(self
.dec
)
930 m
.submodules
.dec_c
= dec_c
= DecodeC(self
.dec
)
931 m
.submodules
.dec_o
= dec_o
= DecodeOut(self
.dec
)
932 m
.submodules
.dec_o2
= dec_o2
= DecodeOut2(self
.dec
)
933 m
.submodules
.dec_cr_in
= self
.dec_cr_in
= DecodeCRIn(self
.dec
)
934 m
.submodules
.dec_cr_out
= self
.dec_cr_out
= DecodeCROut(self
.dec
)
936 # and SVP64 Extra decoders
937 m
.submodules
.crout_svdec
= crout_svdec
= SVP64CRExtra()
938 m
.submodules
.crin_svdec
= crin_svdec
= SVP64CRExtra()
939 m
.submodules
.crin_svdec_b
= crin_svdec_b
= SVP64CRExtra()
940 m
.submodules
.crin_svdec_o
= crin_svdec_o
= SVP64CRExtra()
941 m
.submodules
.in1_svdec
= in1_svdec
= SVP64RegExtra()
942 m
.submodules
.in2_svdec
= in2_svdec
= SVP64RegExtra()
943 m
.submodules
.in3_svdec
= in3_svdec
= SVP64RegExtra()
944 m
.submodules
.o_svdec
= o_svdec
= SVP64RegExtra()
945 m
.submodules
.o2_svdec
= o2_svdec
= SVP64RegExtra()
947 # debug access to crout_svdec (used in get_pdecode_cr_out)
948 self
.crout_svdec
= crout_svdec
950 # get the 5-bit reg data before svp64-munging it into 7-bit plus isvec
951 reg
= Signal(5, reset_less
=True)
953 # copy instruction through...
954 for i
in [do
.insn
, dec_a
.insn_in
, dec_b
.insn_in
,
955 self
.dec_cr_in
.insn_in
, self
.dec_cr_out
.insn_in
,
956 dec_c
.insn_in
, dec_o
.insn_in
, dec_o2
.insn_in
]:
957 comb
+= i
.eq(self
.dec
.opcode_in
)
960 comb
+= self
.dec_cr_in
.sel_in
.eq(op
.cr_in
)
961 comb
+= self
.dec_cr_out
.sel_in
.eq(op
.cr_out
)
962 comb
+= self
.dec_cr_out
.rc_in
.eq(rc_out
)
965 comb
+= self
.do_copy("read_cr_whole", self
.dec_cr_in
.whole_reg
)
966 comb
+= self
.do_copy("write_cr_whole", self
.dec_cr_out
.whole_reg
)
968 # now do the SVP64 munging. op.SV_Etype and op.sv_in1 comes from
969 # PowerDecoder which in turn comes from LDST-RM*.csv and RM-*.csv
970 # which in turn were auto-generated by sv_analysis.py
971 extra
= self
.sv_rm
.extra
# SVP64 extra bits 10:18
975 comb
+= crout_svdec
.idx
.eq(op
.sv_cr_out
) # SVP64 CR out
976 comb
+= self
.cr_out_isvec
.eq(crout_svdec
.isvec
)
979 # CR in - index selection slightly different due to shared CR field sigh
980 cr_a_idx
= Signal(SVEXTRA
)
981 cr_b_idx
= Signal(SVEXTRA
)
983 # these change slightly, when decoding BA/BB. really should have
984 # their own separate CSV column: sv_cr_in1 and sv_cr_in2, but hey
985 comb
+= cr_a_idx
.eq(op
.sv_cr_in
)
986 comb
+= cr_b_idx
.eq(SVEXTRA
.NONE
)
987 with m
.If(op
.sv_cr_in
== SVEXTRA
.Idx_1_2
.value
):
988 comb
+= cr_a_idx
.eq(SVEXTRA
.Idx1
)
989 comb
+= cr_b_idx
.eq(SVEXTRA
.Idx2
)
991 comb
+= self
.cr_in_isvec
.eq(crin_svdec
.isvec
)
992 comb
+= self
.cr_in_b_isvec
.eq(crin_svdec_b
.isvec
)
993 comb
+= self
.cr_in_o_isvec
.eq(crin_svdec_o
.isvec
)
995 # indices are slightly different, BA/BB mess sorted above
996 comb
+= crin_svdec
.idx
.eq(cr_a_idx
) # SVP64 CR in A
997 comb
+= crin_svdec_b
.idx
.eq(cr_b_idx
) # SVP64 CR in B
998 comb
+= crin_svdec_o
.idx
.eq(op
.sv_cr_out
) # SVP64 CR out
1000 # ...and subdecoders' input fields
1001 comb
+= dec_a
.sel_in
.eq(op
.in1_sel
)
1002 comb
+= dec_b
.sel_in
.eq(op
.in2_sel
)
1003 comb
+= dec_c
.sel_in
.eq(op
.in3_sel
)
1004 comb
+= dec_o
.sel_in
.eq(op
.out_sel
)
1005 comb
+= dec_o2
.sel_in
.eq(op
.out_sel
)
1006 if hasattr(do
, "lk"):
1007 comb
+= dec_o2
.lk
.eq(do
.lk
)
1009 # get SVSTATE srcstep (TODO: elwidth, dststep etc.) needed below
1010 srcstep
= Signal
.like(self
.state
.svstate
.srcstep
)
1011 comb
+= srcstep
.eq(self
.state
.svstate
.srcstep
)
1013 # registers a, b, c and out and out2 (LD/ST EA)
1014 for to_reg
, fromreg
, svdec
in (
1015 (e
.read_reg1
, dec_a
.reg_out
, in1_svdec
),
1016 (e
.read_reg2
, dec_b
.reg_out
, in2_svdec
),
1017 (e
.read_reg3
, dec_c
.reg_out
, in3_svdec
),
1018 (e
.write_reg
, dec_o
.reg_out
, o_svdec
),
1019 (e
.write_ea
, dec_o2
.reg_out
, o2_svdec
)):
1020 comb
+= svdec
.extra
.eq(extra
) # EXTRA field of SVP64 RM
1021 comb
+= svdec
.etype
.eq(op
.SV_Etype
) # EXTRA2/3 for this insn
1022 comb
+= svdec
.reg_in
.eq(fromreg
.data
) # 3-bit (CR0/BC/BFA)
1023 comb
+= to_reg
.ok
.eq(fromreg
.ok
)
1024 # detect if Vectorised: add srcstep if yes. TODO: a LOT.
1025 # this trick only holds when elwidth=default and in single-pred
1026 with m
.If(svdec
.isvec
):
1027 comb
+= to_reg
.data
.eq(srcstep
+svdec
.reg_out
) # 7-bit output
1029 comb
+= to_reg
.data
.eq(svdec
.reg_out
) # 7-bit output
1031 comb
+= in1_svdec
.idx
.eq(op
.sv_in1
) # SVP64 reg #1 (matches in1_sel)
1032 comb
+= in2_svdec
.idx
.eq(op
.sv_in2
) # SVP64 reg #2 (matches in2_sel)
1033 comb
+= in3_svdec
.idx
.eq(op
.sv_in3
) # SVP64 reg #3 (matches in3_sel)
1034 comb
+= o_svdec
.idx
.eq(op
.sv_out
) # SVP64 output (matches out_sel)
1035 # XXX TODO - work out where this should come from. the problem is
1036 # that LD-with-update is implied (computed from "is instruction in
1037 # "update mode" rather than specified cleanly as its own CSV column
1038 #comb += o2_svdec.idx.eq(op.sv_out) # SVP64 output (implicit)
1040 # output reg-is-vectorised (and when no input or output is vectorised)
1041 comb
+= self
.in1_isvec
.eq(in1_svdec
.isvec
)
1042 comb
+= self
.in2_isvec
.eq(in2_svdec
.isvec
)
1043 comb
+= self
.in3_isvec
.eq(in3_svdec
.isvec
)
1044 comb
+= self
.o_isvec
.eq(o_svdec
.isvec
)
1045 comb
+= self
.o2_isvec
.eq(o2_svdec
.isvec
)
1046 # TODO add SPRs here. must be True when *all* are scalar
1047 l
= map(lambda svdec
: svdec
.isvec
, [in1_svdec
, in2_svdec
, in3_svdec
,
1048 crin_svdec
, crin_svdec_b
, crin_svdec_o
])
1049 comb
+= self
.no_in_vec
.eq(~
Cat(*l
).bool()) # all input scalar
1050 l
= map(lambda svdec
: svdec
.isvec
, [o2_svdec
, o_svdec
, crout_svdec
])
1051 comb
+= self
.no_out_vec
.eq(~
Cat(*l
).bool()) # all output scalar
1054 comb
+= e
.read_spr1
.eq(dec_a
.spr_out
)
1055 comb
+= e
.write_spr
.eq(dec_o
.spr_out
)
1058 comb
+= e
.read_fast1
.eq(dec_a
.fast_out
)
1059 comb
+= e
.read_fast2
.eq(dec_b
.fast_out
)
1060 comb
+= e
.write_fast1
.eq(dec_o
.fast_out
)
1061 comb
+= e
.write_fast2
.eq(dec_o2
.fast_out
)
1063 # condition registers (CR)
1064 for to_reg
, cr
, name
, svdec
in (
1065 (e
.read_cr1
, self
.dec_cr_in
, "cr_bitfield", crin_svdec
),
1066 (e
.read_cr2
, self
.dec_cr_in
, "cr_bitfield_b", crin_svdec_b
),
1067 (e
.read_cr3
, self
.dec_cr_in
, "cr_bitfield_o", crin_svdec_o
),
1068 (e
.write_cr
, self
.dec_cr_out
, "cr_bitfield", crout_svdec
)):
1069 fromreg
= getattr(cr
, name
)
1070 comb
+= svdec
.extra
.eq(extra
) # EXTRA field of SVP64 RM
1071 comb
+= svdec
.etype
.eq(op
.SV_Etype
) # EXTRA2/3 for this insn
1072 comb
+= svdec
.cr_in
.eq(fromreg
.data
) # 3-bit (CR0/BC/BFA)
1073 with m
.If(svdec
.isvec
):
1074 # check if this is CR0 or CR1: treated differently
1075 # (does not "listen" to EXTRA2/3 spec for a start)
1076 # also: the CRs start from completely different locations
1077 with m
.If(cr
.sv_override
== 1): # CR0
1078 offs
= SVP64CROffs
.CR0
1079 comb
+= to_reg
.data
.eq(srcstep
+offs
)
1080 with m
.Elif(cr
.sv_override
== 2): # CR1
1081 offs
= SVP64CROffs
.CR1
1082 comb
+= to_reg
.data
.eq(srcstep
+1)
1084 comb
+= to_reg
.data
.eq(srcstep
+svdec
.cr_out
) # 7-bit output
1086 comb
+= to_reg
.data
.eq(svdec
.cr_out
) # 7-bit output
1087 comb
+= to_reg
.ok
.eq(fromreg
.ok
)
1089 # sigh this is exactly the sort of thing for which the
1090 # decoder is designed to not need. MTSPR, MFSPR and others need
1091 # access to the XER bits. however setting e.oe is not appropriate
1092 with m
.If(op
.internal_op
== MicrOp
.OP_MFSPR
):
1093 comb
+= e
.xer_in
.eq(0b111) # SO, CA, OV
1094 with m
.If(op
.internal_op
== MicrOp
.OP_CMP
):
1095 comb
+= e
.xer_in
.eq(1<<XERRegs
.SO
) # SO
1096 with m
.If(op
.internal_op
== MicrOp
.OP_MTSPR
):
1097 comb
+= e
.xer_out
.eq(1)
1099 # set the trapaddr to 0x700 for a td/tw/tdi/twi operation
1100 with m
.If(op
.internal_op
== MicrOp
.OP_TRAP
):
1101 # *DO NOT* call self.trap here. that would reset absolutely
1102 # everything including destroying read of RA and RB.
1103 comb
+= self
.do_copy("trapaddr", 0x70) # strip first nibble
1105 ####################
1106 # ok so the instruction's been decoded, blah blah, however
1107 # now we need to determine if it's actually going to go ahead...
1108 # *or* if in fact it's a privileged operation, whether there's
1109 # an external interrupt, etc. etc. this is a simple priority
1110 # if-elif-elif sequence. decrement takes highest priority,
1111 # EINT next highest, privileged operation third.
1113 # check if instruction is privileged
1114 is_priv_insn
= instr_is_priv(m
, op
.internal_op
, e
.do
.insn
)
1116 # different IRQ conditions
1117 ext_irq_ok
= Signal()
1118 dec_irq_ok
= Signal()
1123 comb
+= ext_irq_ok
.eq(ext_irq
& msr
[MSR
.EE
]) # v3.0B p944 (MSR.EE)
1124 comb
+= dec_irq_ok
.eq(dec_spr
[63] & msr
[MSR
.EE
]) # 6.5.11 p1076
1125 comb
+= priv_ok
.eq(is_priv_insn
& msr
[MSR
.PR
])
1126 comb
+= illeg_ok
.eq(op
.internal_op
== MicrOp
.OP_ILLEGAL
)
1128 # LD/ST exceptions. TestIssuer copies the exception info at us
1129 # after a failed LD/ST.
1130 with m
.If(exc
.happened
):
1131 with m
.If(exc
.alignment
):
1132 self
.trap(m
, TT
.PRIV
, 0x600)
1133 with m
.Elif(exc
.instr_fault
):
1134 with m
.If(exc
.segment_fault
):
1135 self
.trap(m
, TT
.PRIV
, 0x480)
1137 # pass exception info to trap to create SRR1
1138 self
.trap(m
, TT
.MEMEXC
, 0x400, exc
)
1140 with m
.If(exc
.segment_fault
):
1141 self
.trap(m
, TT
.PRIV
, 0x380)
1143 self
.trap(m
, TT
.PRIV
, 0x300)
1145 # decrement counter (v3.0B p1099): TODO 32-bit version (MSR.LPCR)
1146 with m
.Elif(dec_irq_ok
):
1147 self
.trap(m
, TT
.DEC
, 0x900) # v3.0B 6.5 p1065
1149 # external interrupt? only if MSR.EE set
1150 with m
.Elif(ext_irq_ok
):
1151 self
.trap(m
, TT
.EINT
, 0x500)
1153 # privileged instruction trap
1154 with m
.Elif(priv_ok
):
1155 self
.trap(m
, TT
.PRIV
, 0x700)
1157 # illegal instruction must redirect to trap. this is done by
1158 # *overwriting* the decoded instruction and starting again.
1159 # (note: the same goes for interrupts and for privileged operations,
1160 # just with different trapaddr and traptype)
1161 with m
.Elif(illeg_ok
):
1162 # illegal instruction trap
1163 self
.trap(m
, TT
.ILLEG
, 0x700)
1165 # no exception, just copy things to the output
1169 ####################
1170 # follow-up after trap/irq to set up SRR0/1
1172 # trap: (note e.insn_type so this includes OP_ILLEGAL) set up fast regs
1173 # Note: OP_SC could actually be modified to just be a trap
1174 with m
.If((do_out
.insn_type
== MicrOp
.OP_TRAP
) |
1175 (do_out
.insn_type
== MicrOp
.OP_SC
)):
1176 # TRAP write fast1 = SRR0
1177 comb
+= e_out
.write_fast1
.data
.eq(FastRegs
.SRR0
) # constant: SRR0
1178 comb
+= e_out
.write_fast1
.ok
.eq(1)
1179 # TRAP write fast2 = SRR1
1180 comb
+= e_out
.write_fast2
.data
.eq(FastRegs
.SRR1
) # constant: SRR1
1181 comb
+= e_out
.write_fast2
.ok
.eq(1)
1183 # RFID: needs to read SRR0/1
1184 with m
.If(do_out
.insn_type
== MicrOp
.OP_RFID
):
1185 # TRAP read fast1 = SRR0
1186 comb
+= e_out
.read_fast1
.data
.eq(FastRegs
.SRR0
) # constant: SRR0
1187 comb
+= e_out
.read_fast1
.ok
.eq(1)
1188 # TRAP read fast2 = SRR1
1189 comb
+= e_out
.read_fast2
.data
.eq(FastRegs
.SRR1
) # constant: SRR1
1190 comb
+= e_out
.read_fast2
.ok
.eq(1)
1192 # annoying simulator bug
1193 if hasattr(e_out
, "asmcode") and hasattr(self
.dec
.op
, "asmcode"):
1194 comb
+= e_out
.asmcode
.eq(self
.dec
.op
.asmcode
)
1198 def trap(self
, m
, traptype
, trapaddr
, exc
=None):
1199 """trap: this basically "rewrites" the decoded instruction as a trap
1202 op
, e
= self
.dec
.op
, self
.e
1203 comb
+= e
.eq(0) # reset eeeeeverything
1206 comb
+= self
.do_copy("insn", self
.dec
.opcode_in
, True)
1207 comb
+= self
.do_copy("insn_type", MicrOp
.OP_TRAP
, True)
1208 comb
+= self
.do_copy("fn_unit", Function
.TRAP
, True)
1209 comb
+= self
.do_copy("trapaddr", trapaddr
>> 4, True) # bottom 4 bits
1210 comb
+= self
.do_copy("traptype", traptype
, True) # request type
1211 comb
+= self
.do_copy("ldst_exc", exc
, True) # request type
1212 comb
+= self
.do_copy("msr", self
.state
.msr
, True) # copy of MSR "state"
1213 comb
+= self
.do_copy("cia", self
.state
.pc
, True) # copy of PC "state"
1217 def get_rdflags(e
, cu
):
1219 for idx
in range(cu
.n_src
):
1220 regfile
, regname
, _
= cu
.get_in_spec(idx
)
1221 rdflag
, read
= regspec_decode_read(e
, regfile
, regname
)
1223 print("rdflags", rdl
)
1227 if __name__
== '__main__':
1228 pdecode
= create_pdecode()
1229 dec2
= PowerDecode2(pdecode
)
1230 vl
= rtlil
.convert(dec2
, ports
=dec2
.ports() + pdecode
.ports())
1231 with
open("dec2.il", "w") as f
: