Annotation of gforth/arch/mips/disasm.fs, revision 1.5

1.1       anton       1: \ disasm.fs    disassembler file (for MIPS R3000)
                      2: \
                      3: \ Copyright (C) 1995-97 Martin Anton Ertl, Christian Pirker
                      4: \
                      5: \ This file is part of RAFTS.
                      6: \
                      7: \      RAFTS is free software; you can redistribute it and/or
                      8: \      modify it under the terms of the GNU General Public License
                      9: \      as published by the Free Software Foundation; either version 2
                     10: \      of the License, or (at your option) any later version.
                     11: \
                     12: \      This program is distributed in the hope that it will be useful,
                     13: \      but WITHOUT ANY WARRANTY; without even the implied warranty of
                     14: \      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
                     15: \      GNU General Public License for more details.
                     16: \
                     17: \      You should have received a copy of the GNU General Public License
                     18: \      along with this program; if not, write to the Free Software
                     19: \      Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
                     20: 
1.4       anton      21: \ this disassembler is based on data from the R4400 manual
                     22: \ http://www.mips.com/Documentation/R4400_Uman_book_Ed2.pdf, in
                     23: \ particular pages A3,A181,A182 (offset 468 pages in xpdf).
                     24: \ it is limited to the R3000 (MIPS-I) architecture, though.
1.2       anton      25: 
1.4       anton      26: \ instruction fields
1.3       anton      27: 
                     28: : disasm-op ( w -- u )
                     29:     26 rshift ;
                     30: 
                     31: : disasm-rs ( w -- u )
                     32:     21 rshift $1F and ;
                     33: 
                     34: : disasm-rt ( w -- u )
                     35:     16 rshift $1f and ;
                     36: 
                     37: : disasm-rd ( w -- u )
                     38:     11 rshift $1f and ;
                     39: 
                     40: : disasm-shamt ( w -- u )
                     41:     \ shift amount field
                     42:     6 rshift $1f and ;
                     43: 
                     44: : disasm-funct ( w -- u )
                     45:     $3f and ;
                     46: 
                     47: : disasm-copz ( w -- u )
                     48:     disasm-op 3 and ;
                     49: 
1.5     ! anton      50: : disasm-uimm ( w -- u )
        !            51:     $ffff and ;
        !            52: 
1.3       anton      53: : disasm-imm ( w -- n )
1.5     ! anton      54:     disasm-uimm dup 15 rshift negate 15 lshift or ;
1.3       anton      55: 
                     56: : disasm-relative ( addr n -- w )
                     57:     \ compute printable form of relative address n relative to addr
                     58:     nip ( + ) ;
                     59: 
1.4       anton      60: \ decode tables
                     61: 
                     62: : disasm-illegal ( addr w -- )
                     63:     \ disassemble illegal/unknown instruction w at addr
                     64:     hex. ." , ( illegal inst ) " drop ;
                     65: 
                     66: : disasm-table ( n "name" -- )
                     67:     \ initialize table with n entries with disasm-illegal
                     68:     create 0 ?do
                     69:        ['] disasm-illegal ,
                     70:     loop
                     71: does> ( u -- addr )
                     72:     swap cells + ;
                     73: 
                     74: $40 disasm-table opc-tab-entry     \ top-level decode table
                     75: $40 disasm-table funct-tab-entry   \ special function table
                     76: $20 disasm-table regimm-tab-entry  \ regim instructions rt table
                     77: $20 disasm-table copz-rs-tab-entry \ COPz instructions rs table
                     78: $20 disasm-table copz-rt-tab-entry \ COPz BC instructions rt table
                     79: $40 disasm-table cp0-tab-entry     \ COP0 CO instructions funct table
                     80: 
1.3       anton      81: \ disassembler central decode cascade
                     82: 
                     83: : disasm-inst ( addr w -- )
                     84:     \G disassemble instruction w at addr (addr is used for computing
                     85:     \G branch targets)
1.4       anton      86:     dup disasm-op opc-tab-entry @ execute ;
1.3       anton      87: 
                     88: : disasm-dump ( addr u -- ) \ gforth
                     89:     \G disassemble u aus starting at addr
                     90:     bounds u+do
                     91:        cr ." ( " i hex. ." ) " i i @ disasm-inst
                     92:        1 cells +loop ;
                     93: 
                     94: : disasm-special ( addr w -- )
                     95:     \ disassemble inst with opcode special
1.4       anton      96:     dup disasm-funct funct-tab-entry @ execute ;
                     97: ' disasm-special 0 opc-tab-entry ! \ enter it for opcode special
1.3       anton      98: 
                     99: : disasm-regimm ( addr w -- )
                    100:     \ disassemble regimm inst
1.4       anton     101:     dup disasm-rt regimm-tab-entry @ execute ;
                    102: ' disasm-regimm 1 opc-tab-entry ! \ enter it for opcode regimm
1.3       anton     103: 
                    104: : disasm-copz-rs ( addr w -- )
                    105:     \ disassemble inst with opcode COPz
1.4       anton     106:     dup disasm-rs copz-rs-tab-entry @ execute ;
                    107: ' disasm-copz-rs $10 opc-tab-entry ! \ enter it for opcodes COPz
                    108: ' disasm-copz-rs $11 opc-tab-entry !
                    109: ' disasm-copz-rs $12 opc-tab-entry !
1.3       anton     110: 
                    111: : disasm-copz-rt ( addr w -- )
                    112:     \ disassemble inst with opcode COPz, rs=BC
1.4       anton     113:     dup disasm-rt copz-rt-tab-entry @ execute ;
                    114: ' disasm-copz-rt $08 copz-rs-tab-entry ! \ into COPz-table for rs=BC
1.3       anton     115: 
                    116: : disasm-cp0 ( addr w -- )
                    117:     \ disassemble inst with opcode COPz, rs=CO
1.4       anton     118:     dup disasm-funct cp0-tab-entry @ execute ;
                    119: ' disasm-cp0 $10 copz-rs-tab-entry ! \ into COPz-table for rs=CO
1.3       anton     120: 
1.4       anton     121: \ dummy words for insts.fs (words with these names are needed by asm.fs)
1.3       anton     122: 
                    123: : asm-op ( -- ) ;
1.4       anton     124: : asm-rs ( -- ) ;
                    125: : asm-rt ( -- ) ;
                    126: 
                    127: \ disassemble various formats
1.3       anton     128: 
                    129: : disasm-J-target ( addr w -- )
                    130:     \ print jump target
                    131:     $3ffffff and swap $fc000000 and or hex. ;
                    132: 
                    133: : disasm-I-rs,rt,imm ( addr w -- )
                    134:     dup disasm-rs .
                    135:     dup disasm-rt .
                    136:     disasm-imm disasm-relative . ;
                    137: 
                    138: : disasm-I-rs,imm ( addr w -- )
                    139:     dup disasm-rs .
                    140:     disasm-imm disasm-relative . ;
                    141: 
                    142: : disasm-rt,rs,imm ( addr w -- )
                    143:     dup disasm-rt .
                    144:     dup disasm-rs .
                    145:     disasm-imm .
                    146:     drop ;
1.1       anton     147: 
1.5     ! anton     148: : disasm-rt,rs,uimm ( addr w -- )
1.3       anton     149:     dup disasm-rt .
1.5     ! anton     150:     dup disasm-rs .
        !           151:     disasm-uimm hex.
        !           152:     drop ;
        !           153: 
        !           154: : disasm-rt,uimm ( addr w -- )
        !           155:     dup disasm-rt .
        !           156:     disasm-uimm hex.
1.1       anton     157:     drop ;
                    158: 
1.3       anton     159: : disasm-rt,imm,rs ( addr w -- )
                    160:     dup disasm-rt .
                    161:     dup disasm-imm .
                    162:     dup disasm-rs .
                    163:     2drop ;
                    164: 
                    165: : disasm-rd,rt,sa ( addr w -- )
                    166:     dup disasm-rd .
                    167:     dup disasm-rt .
                    168:     dup disasm-shamt .
                    169:     2drop ;
                    170: 
                    171: : disasm-rd,rt,rs ( addr w -- )
                    172:     dup disasm-rd .
                    173:     dup disasm-rt .
                    174:     dup disasm-rs .
                    175:     2drop ;
                    176: 
                    177: : disasm-rs. ( addr w -- )
                    178:     dup disasm-rs .
                    179:     2drop ;
                    180: 
                    181: : disasm-rd,rs ( addr w -- )
                    182:     dup disasm-rd .
                    183:     dup disasm-rs .
                    184:     2drop ;
                    185: 
                    186: : disasm-rd. ( addr w -- )
                    187:     dup disasm-rd .
                    188:     2drop ;
                    189: 
                    190: : disasm-rs,rt ( addr w -- )
                    191:     dup disasm-rs .
                    192:     dup disasm-rt .
                    193:     2drop ;
                    194: 
                    195: : disasm-rd,rs,rt ( addr w -- )
                    196:     dup disasm-rd .
                    197:     dup disasm-rs .
                    198:     dup disasm-rt .
                    199:     2drop ;
                    200: 
                    201: : disasm-rt,rd,z ( addr w -- )
                    202:     dup disasm-rt .
                    203:     dup disasm-rd .
                    204:     dup disasm-copz .
                    205:     2drop ;
                    206: 
1.5     ! anton     207: : disasm-I-imm,z ( addr w -- )
        !           208:     tuck disasm-imm disasm-relative .
        !           209:     disasm-copz . ;
1.4       anton     210: 
                    211: \ meta-defining word for instruction format disassembling definitions
                    212: 
                    213: \ The following word defines instruction-format words, which in turn
                    214: \ define anonymous words for disassembling specific instructions and
                    215: \ put them in the appropriate decode table.
                    216: 
                    217: : define-format ( disasm-xt table-xt -- )
                    218:     \ define an instruction format that uses disasm-xt for
                    219:     \ disassembling and enters the defined instructions into table
                    220:     \ table-xt
                    221:     create 2,
                    222: does> ( u "inst" -- )
                    223:     \ defines an anonymous word for disassembling instruction inst,
                    224:     \ and enters it as u-th entry into table-xt
                    225:     2@ swap here name string, ( u table-xt disasm-xt c-addr ) \ remember string
                    226:     noname create 2,      \ define anonymous word
                    227:     execute lastxt swap ! \ enter xt of defined word into table-xt
                    228: does> ( addr w -- )
                    229:     \ disassemble instruction w at addr
                    230:     2@ >r ( addr w disasm-xt R: c-addr )
                    231:     execute ( R: c-addr ) \ disassemble operands
                    232:     r> count type ; \ print name 
                    233: 
                    234: \ all the following words have the stack effect ( u "name" )
                    235: ' disasm-J-target    ' opc-tab-entry    define-format asm-J-target
                    236: ' disasm-I-rs,rt,imm ' opc-tab-entry    define-format asm-I-rs,rt,imm
                    237: ' disasm-I-rs,imm    ' opc-tab-entry    define-format asm-I-rs,imm1
                    238: ' disasm-rt,rs,imm   ' opc-tab-entry    define-format asm-I-rt,rs,imm
1.5     ! anton     239: ' disasm-rt,rs,uimm   ' opc-tab-entry   define-format asm-I-rt,rs,uimm
        !           240: ' disasm-rt,uimm      ' opc-tab-entry   define-format asm-I-rt,uimm
1.4       anton     241: ' disasm-rt,imm,rs   ' opc-tab-entry    define-format asm-I-rt,offset,rs
                    242: ' disasm-rd,rt,sa    ' funct-tab-entry          define-format asm-special-rd,rt,sa
                    243: ' disasm-rd,rt,rs    ' funct-tab-entry          define-format asm-special-rd,rt,rs
                    244: ' disasm-rs.         ' funct-tab-entry          define-format asm-special-rs
                    245: ' disasm-rd,rs       ' funct-tab-entry          define-format asm-special-rd,rs
                    246: ' 2drop              ' funct-tab-entry          define-format asm-special-nothing
                    247: ' disasm-rd.         ' funct-tab-entry          define-format asm-special-rd
                    248: ' disasm-rs,rt       ' funct-tab-entry          define-format asm-special-rs,rt
                    249: ' disasm-rd,rs,rt    ' funct-tab-entry          define-format asm-special-rd,rs,rt
                    250: ' disasm-I-rs,imm    ' regimm-tab-entry  define-format asm-regimm-rs,imm
                    251: ' 2drop              ' cp0-tab-entry     define-format asm-copz0
                    252: ' disasm-rt,rd,z     ' copz-rs-tab-entry define-format asm-copz-rt,rd1
1.5     ! anton     253: ' disasm-I-imm,z     ' copz-rt-tab-entry define-format asm-copz-imm1
1.4       anton     254: 
                    255: : asm-I-rs,imm ( u1 u2 "name" -- ; compiled code: addr w -- )
                    256:     nip asm-I-rs,imm1 ;
                    257: 
1.3       anton     258: : asm-copz-rt,rd ( u1 u2 "name" -- )
1.4       anton     259:     drop asm-copz-rt,rd1 ;
1.3       anton     260: 
1.4       anton     261: : asm-copz-rt,offset,rs ( u "name" -- )
                    262:     \ ignore these insts, we disassemble using  asm-I-rt,offset,rs
                    263:     drop name 2drop ;
1.3       anton     264: 
                    265: : asm-copz-imm ( u1 u2 u3 "name" -- )
1.4       anton     266:     drop nip asm-copz-imm1 ;
1.1       anton     267: 
1.3       anton     268: include ./insts.fs

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