1# $NetBSD: README.models,v 1.7 2021/05/28 00:18:27 simonb Exp $
2
3MIPS models and architecture levels
4-----------------------------------
5
6Since this is a complex and confusing topic and there's a shortage of
7information (especially, a shortage of reliable information), I'm
8creating this document as a reference for people doing MIPS stuff on
9NetBSD (and elsewhere).
10
11Citations appear in []. With luck all important facts have citations.
12
13
14------------------------------------------------------------
151. Architecture levels.
16
17These architecture levels exist:
18
19 32-bit 64-bit
20
21 MIPS-I
22 MIPS-II
23 MIPS-III
24 MIPS-IV
25 MIPS-V
26 MIPS32 MIPS64
27 MIPS32r2 MIPS64r2
28 MIPS32r3 MIPS64r3
29 MIPS32r5 MIPS64r5
30 MIPS32r6 MIPS64r6
31
32Note that while MIPS32 is a 32-bit subset of MIPS64, each
33corresponding pair of MIPS32rN and MIPS64rN are comparable in age and
34properties. Later revisions (further down the list) are mostly supersets
35of earlier revisions, although some exceptions exist.
36
37
38------------------------------------------------------------
392. CPU models.
40
41For vintage MIPS these are the standard models as of fall 1996 [idt96
42A-198] and the corresponding architecture levels. (There were many
43additional models put out by licensees or by the MIPS company itself,
44which have model numbers with fewer zeros.)
45
46 R2000 MIPS-I (32-bit) [idt96 1-5]
47 R3000 MIPS-I (32-bit) [idt96 1-5]
48 R4000 MIPS-III (64-bit) [idt96 A-197]
49 R4200 MIPS-III (64-bit) [idt96 A-197]
50 R4300 MIPS-III (64-bit) [idt96 A-197]
51 R4400 MIPS-III (64-bit) [idt96 A-197]
52 R4600 MIPS-III (64-bit) [idt96 A-197]
53 R5000 MIPS-IV (64-bit) [idt96 1-5]
54 R6000 MIPS-II (32-bit) with 64-bit FPU regs
55 R8000 MIPS-IV (64-bit) [idt96 1-5]
56 R10000 MIPS-IV (64-bit) [idt96 1-5]
57 R1x000 MIPS-IV (64-bit)
58
59For later models than this I currently have no information.
60
61
62------------------------------------------------------------
633. CPU models present in various systems.
64
65These are the CPU models found in various systems NetBSD does and
66doesn't support. This table also notes endianness; MIPS chips are
67bi-endian but are wired up one way or the other on motherboards.
68
69 algor (little-endian [buildsh])
70 Algorithmics P-4000i ??
71 Algorithmics P-4032 ??
72 Algorithmics P-5064 ??
73 Algorithmics P-6032 ??
74 arc (little-endian [buildsh])
75 Acer PICA ??
76 MIPS Magnum 4000 ??
77 NEC Image RISCstation ??
78 NEC Express RISCserver ??
79 NEC RISCserver 2200 ??
80 NEC RISCstation 2200 ??
81 NEC RISCstation 2250 ??
82 NEC Express5800/230 R4400 PCI presumably R4400 (MIPS-III)
83 NEC Express5800/240 R4400 EISA presumably R4400 (MIPS-III)
84 DeskStation Tyne ??
85 cobalt (little-endian [buildsh])
86 Qube ... ?? ??
87 RaQ ... ?? ??
88 emips (big-endian [buildsh])
89 ... ?? ??
90 (see http://research.microsoft.com/en-us/projects/emips/ )
91 evbmips
92 Loongson 2F ( gdium, lemote etc. ) more or less LE MIPS-III with
93 some extensions
94 xburst ( as in, jz4780, found on CI20 ) LE MIPS32R2 with extensions
95 ... ?? ?? (various-endian)
96 ews4800mips (big-endian [buildsh])
97 EWS4800/350 ??
98 EWS4800/350F ??
99 EWS4800/360AD ??
100 EWS4800/360ADII ??
101 EWS4800/360SX ??
102 EWS4800/360EX ??
103 EWS4800/360 ??
104 ... ?? ??
105 hpcmips (big-endian [buildsh])
106 see http://wiki.netbsd.org/ports/hpcmips/processor_comparison/
107 mipsco (big-endian [buildsh])
108 Various MIPS Computer Systems, Inc. see [mipscolist]
109 Bull DPX/Prostation M-20 ??
110 newsmips (big-endian [buildsh])
111 NWS-3470D R3000 (MIPS-I) [portpage]
112 NWS-3410 R3000 (MIPS-I) [portpage]
113 NWS-3460 R3000 (MIPS-I) [portpage]
114 NWS-3710 R3000 (MIPS-I) [portpage]
115 NWS-3720 R3000 (MIPS-I) [portpage]
116 NWS-3800 series ??
117 NWS-4000 series R4600 (MIPS-III) [portpage]
118 NWS-5000 R4[04]00 (MIPS-III) [portpage]
119 playstation2 (little-endian [buildsh])
120 playstation2 R5900
121 (almost all of MIPS-III + movn/movz) [linux-mips wiki R5900]
122 pmax (little-endian [buildsh])
123 DECstation/system 2100 and 3100 R2000 (MIPS-I) [portpage]
124 DECsystem 5100 R3000 (MIPS-I) [portpage]
125 Personal DECstation 5000/20, /25, /33 R3000 (MIPS-I) [portpage]
126 Personal DECstation 5000/50 R4000 (MIPS-III) [portpage]
127 DECstation/system 5000/120, /125, /133 R3000 (MIPS-I) [portpage]
128 DECstation/system 5000/150 R4000 (MIPS-III) [portpage]
129 DECstation/system 5000/200 R3000 (MIPS-I) [portpage]
130 DECstation/system 5000/240 R3000 (MIPS-I) [portpage]
131 DECstation/system 5000/260 R4400 (MIPS-III) [portpage]
132 DECsystem 5900 R3000 (MIPS-I) [portpage]
133 DECsystem 5900-260 R4400 (MIPS-III) [portpage]
134 DECsystem 5500 R3000 (MIPS-I) [portpage]
135 sbmips
136 BCM91250A (Swarm) evaluation board Broadcomm BCM1250 [portpage]
137 sgimips (big-endian [buildsh])
138 4D/20 ??
139 4D/25 ??
140 Indigo R3000 (MIPS-I) [portpage]
141 Indigo (R4x00) R4?00 (MIPS-III) [portpage]
142 4D/30 ??
143 4D/35 ??
144 Indigo2 (R4x00) R4?00 (MIPS-III) [portpage]
145 Challenge M ??
146 Indy (R4x00) R4?00 (MIPS-III) [portpage]
147 Indy (R5000) R5000 (MIPS-IV) [portpage]
148 Challenge S (R4x00) R4?00 (MIPS-III) [portpage]
149 Challenge S (R5000) R5000 (MIPS-IV) [portpage]
150 R10000 Power Indigo2 R10000 (MIPS-IV) [portpage]
151 Octane R1x000 (MIPS-IV) [portpage]
152 O2 (R5000) R5000 (MIPS-IV) [portpage]
153 O2 (RM5200) RM5200 (MIPS-IV) [portpage]
154 O2 (R7000) R7000 (MIPS-IV) [portpage]
155 O2 (R10000) R10000 (MIPS-IV) [portpage]
156 O2 (R12000) R12000 (MIPS-IV) [portpage]
157 O2 (R14000) R14000 (MIPS-IV) [portpage]
158 Fuel R1x000 (MIPS-IV) [portpage]
159 Tezro R1x000 (MIPS-IV) [portpage]
160 ... ??
161
162
163------------------------------------------------------------
1644. FPU properties
165
166TBD... this is complex and messy (XXX / ??)
167
168
169------------------------------------------------------------
1705. Exception handling properties
171
172TBD... (XXX / ??)
173
174
175------------------------------------------------------------
1766. MMU properties
177
178TBD... (XXX / ??)
179
180
181------------------------------------------------------------
1827. Cache properties
183
184TBD... (XXX / ??)
185
186
187------------------------------------------------------------
1888. Instruction ordering properties and hazards
189
190TBD... (XXX / ??)
191
192In the absence of the SYNC instruction before MIPS-II [idt96 A-172,
193mips32insn 215], apparently on a R3000 you can force pending memory
194writes to complete by doing an uncached read. [idt96 11-13]
195
196Apparently also on some models but not others the state of the write
197buffer is wired to the coprocessor 0 condition bit and you can also do
198this by using the otherwise useless bc0f instruction (branch on
199coprocessor 0 false) to loop. [no citation, I found this in passing
200the other day with Google while looking for something else]
201
202
203------------------------------------------------------------
2049. Pipeline hazards
205
206TBD... (XXX / ??)
207
208On MIPS-I a load instruction requires an explicit one-cycle wait
209before using the result. This restriction was lifted in MIPS-II,
210with the addition of an interlock in the pipeline. [idt96 A-2]
211
212A multiply should not be started within two cycles of a MFHI or MFLO
213instruction, as an interrupt that requires restarting the MFHI or MFLO
214might (will) get the result from the subsequent multiply. At least on
215MIPS-I. [idt96 2-4] I guess this is true for divides as well.
216
217
218------------------------------------------------------------
21910. Coprocessor 0 hazards
220
221TBD... (XXX / ??)
222
223
224----------------------------------------------------------------------
22511. Deprecated/removed material.
226
227When the exception handling model was changed for MIPS-III
228(introducing the ERET instruction) the RFE instruction supporting the
229old model was removed. [idt96 A-134]
230
231Coprocessor 3 (that is, the ability to have a third coprocessor, which
232had never been used for anything) was removed in MIPS-III [idt96 A-197].
233
234The branch likely instructions (e.g. BEQL) were added in MIPS-II
235[mips32insn 56] and deprecated not long after, at least by MIPS32
236[mips32insn 57] and were removed in release MIPS32 Release 6
237[mips32newinsn2a 71].
238
239SSNOP as a special NOP was deprecated in MIPS32/64 Release 6
240[mips32newinsn2a 375] and sequences using SSNOP should include the
241new EHB which counts as an SSNOP on older implementations
242[mips32newinsn2a 174] ... and possibly SYNC/SYNCI ???
243[mips32newinsn2a 394-401]
244
245... ??
246
247------------------------------------------------------------
24812. Conditional compilation in NetBSD
249
250TBD... (XXX / ??)
251
252
253------------------------------------------------------------
254References:
255
256[buildsh] The MACHINE/MACHINE_ARCH architecture table in NetBSD
257 build.sh.
258
259[idt96] "IDT MIPS Microprocessor Family Software Reference Manual",
260 Integrated Device Technology, Version 2.0, dated October 1996.
261
262[linux-mips wiki] https://www.linux-mips.org/wiki/
263
264[mips32intro] "MIPS32(TM) Architecture For Programmers Volume I:
265 Introduction to the MIPS32(TM) Architecture", MIPS
266 Technologies, Document Number MD00082, Revision 0.95, dated
267 March 2001. This was apparently an external review version or
268 something and has been available on the Internet; the final
269 version, and later revisions, never were. (AFAIK)
270
271[mips32insn] "MIPS32(TM) Architecture For Programmers Volume II: The
272 MIPS32(TM) Instruction Set", MIPS Technologies, Document Number
273 MD00086, Revision 0.95, March 12, 2001. Ditto.
274
275[mips32newinsn2a] "MIPS32(R) Architecture For Programmers Volume II-A:
276 The MIPS32(R) Instruction Set Manual", Imagination, Document
277 Number MD00086, Revision 6.02, dated December 10, 2014.
278
279[mips32priv] "MIPS32(TM) Architecture For Programmers Volume III: The
280 MIPS32(TM) Privileged Resource Architecture", Document Number
281 MD00090, Revision 0.95, dated March 2001. Ditto.
282
283[portpage] The port page for this NetBSD port on wiki.netbsd.org, or a
284 subpage. Ideally these references should be replaced with
285 something less self-referential.
286
287[mipscolist] List of MIPS Computer Systems, Inc. machines hosted on the
288 NetBSD web server: https://www.netbsd.org/ports/mipsco/models.html
289
290