git.sesse.net Git - pistorm/blob - platforms/amiga/cdtv-dmac.c

   1 // SPDX-License-Identifier: MIT
   2
   3 #include <stdio.h>
   4 #include <stdint.h>
   5 #include <stdlib.h>
   6 #include "config_file/config_file.h"
   7
   8 uint8_t dmac_reg_idx = 0;
   9 uint8_t dmac_reg_values[0xFFFF];
  10
  11 uint8_t cdtv_dmac_reg_idx_read() {
  12     return dmac_reg_idx;
  13 }
  14
  15 /* DMAC Registers
  16 R   0x06 [B]    - Something
  17
  18     0x40 [W]    - ISTR
  19 RW  0x42 [W]    - CNTR
  20
  21     0x80 [L]    - WTC
  22     0x84 [L]    - ACR
  23
  24     0x8E [B]    - SASR
  25 W   0x8F [B]    - Something
  26     0x90        - SCMD
  27     0x91 [B]    - Something
  28     0x92 [B]    - Something?
  29 RW  0x93 [B]    - Something
  30
  31 R   0xA2?[W?]   - Some status thing?
  32 W   0xA4?[W?]   - Something
  33 W   0xA6?[W?]   - Something
  34 W   0xA8?[W?]   - Something
  35
  36     0xDE [W]    - ST_DMA
  37     0xE0 [W]    - SP_DMA
  38     0xE2 [W]    - CINT
  39     0xE4 [W]    - Something
  40     0xE4-0xE5   - Nothing
  41     0xE6 [W]    - Flush
  42 */
  43
  44 void cdtv_dmac_reg_idx_write(uint8_t value) {
  45     dmac_reg_idx = value;
  46 }
  47
  48 uint32_t cdtv_dmac_read(uint32_t address, uint8_t type) {
  49     uint32_t ret = 0;
  50
  51     switch (type) {
  52         case OP_TYPE_BYTE:
  53             return dmac_reg_values[address];
  54         case OP_TYPE_WORD:
  55             return be16toh(*((uint16_t *)&dmac_reg_values[address]));
  56         default:
  57             break;
  58     }
  59
  60     return ret;
  61 }
  62
  63 void cdtv_dmac_write(uint32_t address, uint32_t value, uint8_t type) {
  64     switch (type) {
  65         case OP_TYPE_BYTE:
  66             dmac_reg_values[address] = (uint8_t)value;
  67             return ;
  68         case OP_TYPE_WORD:
  69             printf("Help, it's a scary word write.\n");
  70             *((uint16_t *)&dmac_reg_values[address]) = htobe16(value);
  71             return;
  72     }
  73 }