1 # $NetBSD: README.models,v 1.7 2021/05/28 00:18:27 simonb Exp $ 2 3 MIPS models and architecture levels 4 ----------------------------------- 5 6 Since this is a complex and confusing topic and there's a shortage of 7 information (especially, a shortage of reliable information), I'm 8 creating this document as a reference for people doing MIPS stuff on 9 NetBSD (and elsewhere). 10 11 Citations appear in []. With luck all important facts have citations. 12 13 14 ------------------------------------------------------------ 15 1. Architecture levels. 16 17 These 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 32 Note that while MIPS32 is a 32-bit subset of MIPS64, each 33 corresponding pair of MIPS32rN and MIPS64rN are comparable in age and 34 properties. Later revisions (further down the list) are mostly supersets 35 of earlier revisions, although some exceptions exist. 36 37 38 ------------------------------------------------------------ 39 2. CPU models. 40 41 For vintage MIPS these are the standard models as of fall 1996 [idt96 42 A-198] and the corresponding architecture levels. (There were many 43 additional models put out by licensees or by the MIPS company itself, 44 which 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 59 For later models than this I currently have no information. 60 61 62 ------------------------------------------------------------ 63 3. CPU models present in various systems. 64 65 These are the CPU models found in various systems NetBSD does and 66 doesn't support. This table also notes endianness; MIPS chips are 67 bi-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 ------------------------------------------------------------ 164 4. FPU properties 165 166 TBD... this is complex and messy (XXX / ??) 167 168 169 ------------------------------------------------------------ 170 5. Exception handling properties 171 172 TBD... (XXX / ??) 173 174 175 ------------------------------------------------------------ 176 6. MMU properties 177 178 TBD... (XXX / ??) 179 180 181 ------------------------------------------------------------ 182 7. Cache properties 183 184 TBD... (XXX / ??) 185 186 187 ------------------------------------------------------------ 188 8. Instruction ordering properties and hazards 189 190 TBD... (XXX / ??) 191 192 In the absence of the SYNC instruction before MIPS-II [idt96 A-172, 193 mips32insn 215], apparently on a R3000 you can force pending memory 194 writes to complete by doing an uncached read. [idt96 11-13] 195 196 Apparently also on some models but not others the state of the write 197 buffer is wired to the coprocessor 0 condition bit and you can also do 198 this by using the otherwise useless bc0f instruction (branch on 199 coprocessor 0 false) to loop. [no citation, I found this in passing 200 the other day with Google while looking for something else] 201 202 203 ------------------------------------------------------------ 204 9. Pipeline hazards 205 206 TBD... (XXX / ??) 207 208 On MIPS-I a load instruction requires an explicit one-cycle wait 209 before using the result. This restriction was lifted in MIPS-II, 210 with the addition of an interlock in the pipeline. [idt96 A-2] 211 212 A multiply should not be started within two cycles of a MFHI or MFLO 213 instruction, as an interrupt that requires restarting the MFHI or MFLO 214 might (will) get the result from the subsequent multiply. At least on 215 MIPS-I. [idt96 2-4] I guess this is true for divides as well. 216 217 218 ------------------------------------------------------------ 219 10. Coprocessor 0 hazards 220 221 TBD... (XXX / ??) 222 223 224 ---------------------------------------------------------------------- 225 11. Deprecated/removed material. 226 227 When the exception handling model was changed for MIPS-III 228 (introducing the ERET instruction) the RFE instruction supporting the 229 old model was removed. [idt96 A-134] 230 231 Coprocessor 3 (that is, the ability to have a third coprocessor, which 232 had never been used for anything) was removed in MIPS-III [idt96 A-197]. 233 234 The 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]. 238 239 SSNOP as a special NOP was deprecated in MIPS32/64 Release 6 240 [mips32newinsn2a 375] and sequences using SSNOP should include the 241 new EHB which counts as an SSNOP on older implementations 242 [mips32newinsn2a 174] ... and possibly SYNC/SYNCI ??? 243 [mips32newinsn2a 394-401] 244 245 ... ?? 246 247 ------------------------------------------------------------ 248 12. Conditional compilation in NetBSD 249 250 TBD... (XXX / ??) 251 252 253 ------------------------------------------------------------ 254 References: 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
Indexes created Sun Sep 21 18:09:52 GMT 2025