6502 Assmbler in Forth (fig style)#



SCR # 81
0 (  FORTH-65 ASSEMBLER                                WFR-79JUN03 )
1 HEX
2 VOCABULARY  ASSEMBLER  IMMEDIATE       ASSEMBLER   DEFINITIONS
3
4 ( REGISTER ASSIGNMENT SPECIFIC TO IMPLEMENTATION  )
5 E0  CONSTANT  XSAVE       DC  CONSTANT  W      DE  CONSTANT  UP
6 D9  CONSTANT  IP          D1  CONSTANT  N
7
8 (  NUCLEUS LOCATIONS ARE IMPLEMENTATION SPECIFIC )
9 '  (DO)  0E  +    CONSTANT  POP
10 '  (DO)  OC  +    CONSTANT  POPTWO
11 '  LIT  13  +  CONSTANT  PUT
12 '  LIT  11  +  CONSTANT  PUSH
13 '  LIT  18  +  CONSTANT  NEXT
14 '  EXECUTE  NFA  11  -  CONSTANT  SETUP
15

SCR # 82
0 (     ASSEMBLER, CONT.                                WFR-78OCT03 )
1 0   VARIABLE  INDEX       -2   ALLOT
2 0909 , 1505 , 0115 , 8011 ,  8009 , 1DOD ,  8019 ,  8080  ,
3 0080 , 1404 , 8014 , 8080 ,  8080 , 1COC ,  801C ,  2C80  ,
4
5 2  VARIABLE  MODE
6 : .A   0 MODE ! ;    : #     1 MODE ! ;     : MEM   2 MODE  ! ;
7 : ,X   3 MODE ! ;    : ,Y    4 MODE ! ;     : X)    5 MODE  ! ;
8 : )Y   6 MODE ! ;    : )     F MODE ! ;
9
10 : BOT       ,X    0  ;     (  ADDRESS THE BOTTOM OF THE STACK  *)
11 : SEC       ,X    2  ;         ( ADDRESS SECOND ITEM ON STACK  *)
12 : RP)       ,X  101  ;      (  ADDRESS BOTTOM OF RETURN STACK  *)
13
14
15

SCR # 83
0 (  UPMODE,  CPU                                          WFR-78OCT23 )
1
2 :  UPMODE   IF   MODE  @ 8 AND  0=   IF  8  MODE +!   THEN THEN
3       1 MODE @   OF AND   -DUP   IF   0  DO   DUP +  LOOP  THEN
4       OVER 1+ @  AND  0=   ;
5
6 :  CPU   <BUILDS   C,  DOES>   C@    C,  MEM   ;
7       00 CPU BRK,    18 CPU  CLC,    D8 CPU  CLD,   58 CPU CLI,
8       B8 CPU CLV,    CA CPU  DEX,    88 CPU  DEY,   E8 CPU INX,
9       C8 CPU INY,    EA CPU  NOP,    48 CPU  PHA,   08 CPU PHP,
10       68 CPU PLA,    28 CPU  PLP,    40 CPU  RTI,   60 CPU RTS,
11       38 CPU SEC,    F8 CPU  SED,    78 CPU  SEI,   AA CPU TAX,
12       A8 CPU TAY,    BA CFU  TSX,    8A CPU  TXA,   9A CPU TXS,
13       98 CPU TYA,
14
15


SCR #  84
0 (   M/CPU,   MULTI-MODE  OP-CODES                        WFR-79MAR26  )
1 :   M/CPU  <BUILDS  C,   ,  DOES>
2         DUP 1+ @ 80 AND    IF  10  MODE +! THEN    OVER
3         FFOO AND UPMODE  UPMODE     IF MEM CR LATEST  ID.
4         3  ERROR  THEN   C@  MODE   C@
5         INDEX + C@ + C,     MODE C@  7 AND   IF MODE  C@
6         OF AND 7 <   IF C,  ELSE ,  THEN   THEN  MEM   ;
7
8    lC6E  60 M/CPU ADC,  1C6E  20  M/CPU AND,  lC6E C0  M/CPU  CMP,
9    lC6E  40 M/CPU EOR,  1C6E  A0  M/CPU LDA,  1C6E 00  M/CPU  ORA,
10    lC6E  E0 M/CPU SBC,  1C6C  80  M/CPU STA,  0D0D 01  M/CPU  ASL,
11    0C0C  Cl M/CPU DEC,  0C0C  El  M/CPU INC,  0D0D 41  M/CPU  LSR,
12    0D0D  21 M/CPU ROL,  0D0D  61  M/CPU ROR,  0414 81  M/CPU  STX,
13    0486  E0 M/CPU CPX,  0486  C0  M/CPU CPY,  1496 A2  M/CPU  LDX,
14    0C8E  A0 M/CPU LDY,  048C  80  M/CPU STY,  0480 14  M/CPU  JSR,
15    8480  40 M/CPU JMP,  0484  20  M/CPU BIT,



SCR # 85

0 (  ASSEMBLER CONDITIONALS                          WFR-79MAR26  )
1 : BEGIN,   HERE  1  ;                  IMMEDIATE
2 : UNTIL,   ?EXEC >R l ?PAIRS R> C, HERE  1+ - C, ; IMMEDIATE
3 : IF,      C,  HERE  0  C,  2  ;        IMMEDIATE
4 : THEN,    ?EXEC  2  ?PAIRS  HERE  OVER   C@
5         IF  SWAP ! ELSE  OVER 1+ - SWAP  C!  THEN  ; IMMEDIATE
6 : ELSE,    2 ?PAIRS HERE 1+   1 JMP
7            SWAP HERE OVER 1+ - SWAP  C!   2  ; IMMEDIATE
8 : NOT   20   +  ;                    ( REVERSE ASSEMBLY TEST )
9 90  CONSTANT  CS               ( ASSEMBLE TEST FOR CARRY SET )
10 DO  CONSTANT  O=             ( ASSEMBLER TEST FOR EQUAL ZERO )
11 10  CONSTANT  O<          ( ASSEMBLE TEST FOR LESS THAN ZERO )
12 90  CONSTANT  >=   ( ASSEMBLE TEST FOR GREATER OR EQUAL ZERO )
13                     ( >= IS ONLY CORRECT AFTER SUB, OR CMP,  )
14
15


SCR # 86
0 (  USE  OF  ASSEMBLER                                     WFR-79APR28  )
1 : END-CODE                              ( END  OF  CODE   DEFINITION  *)
2       CURRENT   @ CONTEXT  !      ?EXEC ?CSP SMUDGE  ;    IMMEDIATE
3
4 FORTH  DEFINITIONS      DECIMAL
5 : CODE                    ( CREATE  WORD  AT  ASSEMBLY  CODE   LEVEL  *)
6       ? EXEC CREATE    (COMPILE)   ASSEMBLER
7       ASSEMBLER  MEM    !CSP  ;       IMMEDIATE
8
9 ( LOCK ASSEMBLER INTO SYSTEM )
10 '  ASSEMBLER  CFA    '  ;CODE   8   +  !  ( OVER-WRITE SMUDGE )
11 LATEST  12  +ORIGIN  !  ( TOP  NFA  )
12 HERE    28  +ORIGIN  !  ( FENCE  )
13 HERE    30  +ORIGIN  !  ( DP )
14 '  ASSEMBLER  6  +    32  +ORIGIN    !   ( VOC-LINK )
15 HERE  FENCE  !


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« This page (revision-1) was last changed on 05-Apr-2010 21:41 by Carsten Strotmann