sdcc/sdas/asgb/gb.h

   1 /* gb.h */
   2
   3 /*
   4  *  Copyright (C) 1989-2021  Alan R. Baldwin
   5  *
   6  *  This program is free software: you can redistribute it and/or modify
   7  *  it under the terms of the GNU General Public License as published by
   8  *  the Free Software Foundation, either version 3 of the License, or
   9  *  (at your option) any later version.
  10  *
  11  *  This program is distributed in the hope that it will be useful,
  12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  *  GNU General Public License for more details.
  15  *
  16  *  You should have received a copy of the GNU General Public License
  17  *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18  *
  19  *
  20  * Alan R. Baldwin
  21  * 721 Berkeley St.
  22  * Kent, Ohio  44240
  23  */
  24
  25 /* Gameboy mods by Roger Ivie (ivie at cc dot usu dot edu)
  26  *
  27  * The Gameboy mods are based on
  28  * http://www.komkon.org/fms/GameBoy/Tech/Software.html
  29  * by Marat Fayzullin
  30  *
  31  * The Gameboy is allegedly a Z80 with the following mods:
  32  *
  33  * - No index registers
  34  * - No alternate registers
  35  * - No I and R
  36  * - No I/O instructions (all I/O is memory mapped)
  37  * - No parity flag
  38  * - No minus flag
  39  * - No instructions with ED prefix (RETI is moved)
  40  * - HALT is always interruptible, even if interrupts have been disabled.
  41  * - The following instructions are different:
  42  * - No ADC or SBC of r16s.
  43  *
  44  * ----------------------------------------------------------------------------
  45  * Code       Z80 operation  GameBoy operation
  46  * ----------------------------------------------------------------------------
  47  * 08 xx xx   EX AF,AF'      LD (word),SP     Save SP at given address
  48  * 10 xx      DJNZ offset    STOP             Meaning unknown
  49  * 22         LD (word),HL   LD (HLI),A       Save A at (HL) and increment HL
  50  * 2A         LD HL,(word)   LD A,(HLI)       Load A from (HL) and increment HL
  51  * 32         LD (word),A    LD (HLD),A       Save A at (HL) and decrement HL
  52  * 3A         LD A,(word)    LD A,(HLD)       Load A from (HL) and decrement HL
  53  * D3         OUTA (byte)    No operation
  54  * D9         EXX            RETI             Enable interrupts and return
  55  * DB         INA (byte)     No operation
  56  * DD         Prefix DD      No operation
  57  * E0 xx      RET PO         LD (byte),A      Save A at (FF00+byte)
  58  * E2         JP PO,word     LD (C),A         Save A at (FF00+C)
  59  * E3         EX HL,(SP)     No operation
  60  * E4         CALL PO,word   No operation
  61  * E8 xx      RET PE         ADD SP,offset    Add signed offset to SP
  62  * EA xx xx   JP PE,word     LD (word),A      Save A at given address
  63  * EB         EX DE,HL       No operation
  64  * EC         CALL PE,word   No operation
  65  * F0 xx      RET P          LD A,(byte)      Load A from (FF00+byte)
  66  * F2         JP P,word      No operation
  67  * F4         CALL P,word    No operation
  68  * F8 xx      RET M          LDHL SP,offset   Load HL with SP + signed offset
  69  * FA xx xx   JP M,word      LD A,(word)      Load A from given address
  70  * FC         CALL M,word    No operation
  71  * FD         Prefix FD      No operation
  72  * ----------------------------------------------------------------------------
  73  */
  74
  75 /*
  76  * Extensions: P. Felber
  77  */
  78
  79 /*)BUILD
  80         $(PROGRAM) =    ASGB
  81         $(INCLUDE) = {
  82                 ASXXXX.H
  83                 GB.H
  84         }
  85         $(FILES) = {
  86                 GBMCH.C
  87                 GBADR.C
  88                 GBPST.C
  89                 ASMAIN.C
  90                 ASDBG.C
  91                 ASLEX.C
  92                 ASSYM.C
  93                 ASSUBR.C
  94                 ASEXPR.C
  95                 ASDATA.C
  96                 ASLIST.C
  97                 ASOUT.C
  98         }
  99         $(STACK) = 3000
 100 */
 101
 102 /*
 103  * Indirect Addressing delimeters
 104  */
 105 #define LFIND   '('
 106 #define RTIND   ')'
 107
 108 /*
 109  * Registers
 110  */
 111 #define B       0
 112 #define C       1
 113 #define D       2
 114 #define E       3
 115 #define H       4
 116 #define L       5
 117 #define A       7
 118
 119 #define BC      0
 120 #define DE      1
 121 #define HL      2
 122 #define SP      3
 123 #define AF      4
 124 #define HLD     5
 125 #define HLI     6
 126
 127 /*
 128  * Conditional definitions
 129  */
 130 #define NZ      0
 131 #define Z       1
 132 #define NC      2
 133 #define CS      3
 134
 135 /*
 136  * Symbol types
 137  */
 138 #define S_IMMED 30
 139 #define S_R8    31
 140 #define S_R16   33
 141 #define S_R16X  34   /* AF */
 142 #define S_CND   35
 143 #define S_FLAG  36
 144
 145 /*
 146  * Indexing modes
 147  */
 148 #define S_INDB  40
 149 #define S_IDC   41
 150 #define S_INDR  50
 151 #define S_IDBC  50
 152 #define S_IDDE  51
 153 #define S_IDHL  52
 154 #define S_IDSP  53
 155 #define S_IDHLD 55
 156 #define S_IDHLI 56
 157 #define S_INDM  57
 158
 159 /*
 160  * Instruction types
 161  */
 162 #define S_LD    60
 163 #define S_CALL  61
 164 #define S_JP    62
 165 #define S_JR    63
 166 #define S_RET   64
 167 #define S_BIT   65
 168 #define S_INC   66
 169 #define S_DEC   67
 170 #define S_ADD   68
 171 #define S_ADC   69
 172 #define S_AND   70
 173 #define S_PUSH  72
 174
 175 #define S_RL    76
 176 #define S_RST   77
 177 #define S_IM    78
 178 #define S_INH1  79
 179 #define S_SUB   80
 180 #define S_SBC   81
 181 #define S_LDHL  90      /* LDHL SP,offset */
 182 #define S_LDA   91
 183 #define S_STOP  83
 184 #define S_LDH   84
 185 #define S_TILE  93      /* .TILE pseudo-op */
 186
 187 struct adsym
 188 {
 189         char    a_str[4];       /* addressing string */
 190         int     a_val;          /* addressing mode value */
 191 };
 192
 193 extern  struct  adsym   R8[];
 194 extern  struct  adsym   R16[];
 195 extern  struct  adsym   R16X[];
 196 extern  struct  adsym   CND[];
 197
 198         /* machine dependent functions */
 199
 200 #ifdef  OTHERSYSTEM
 201
 202         /* gbadr.c */
 203 extern  int             addr(struct expr *esp);
 204 extern  int             admode(struct adsym *sp);
 205 extern  int             any(int c, char *str);
 206 extern  int             srch(char *str);
 207
 208         /* gbmch.c */
 209 extern  int             genop(int pop, int op, struct expr *esp, int f);
 210 extern  VOID            machine(struct mne *mp);
 211 extern  int             mchpcr(struct expr *esp);
 212 extern  VOID            minit(void);
 213
 214 #else
 215
 216         /* gbadr.c */
 217 extern  int             addr();
 218 extern  int             admode();
 219 extern  int             any();
 220 extern  int             srch();
 221
 222         /* gbmch.c */
 223 extern  int             genop();
 224 extern  VOID            machine();
 225 extern  int             mchpcr();
 226 extern  VOID            minit();
 227
 228 #endif