git.squeep.com Git - dcpu16/blob - hw_clock.c

   1 #include <stdlib.h>
   2 #include <string.h>
   3 #include <errno.h>
   4
   5 #include "dcpu16.h"
   6 #include "hw_clock.h"
   7
   8 #define MSG_(__level__, __vm__, ...) do { ((__vm__) ? ((struct dcpu16 *)(__vm__))->msg_cb_ : dcpu16_msg_)(__level__, __VA_ARGS__); } while (0)
   9 #define MSG_INFO(__vm__, ...) MSG_(DCPU16_MSG_INFO, __vm__, __VA_ARGS__)
  10 #define MSG_ERROR(__vm__, ...) MSG_(DCPU16_MSG_ERROR, __vm__, __VA_ARGS__)
  11 #ifdef DEBUG
  12 #define MSG_DEBUG(__vm__, ...) MSG_(DCPU16_MSG_DEBUG, __vm__, __VA_ARGS__)
  13 #else /* DEBUG  */
  14 #define MSG_DEBUG(__vm__, ...) do { } while (0)
  15 #endif /* DEBUG */
  16
  17 struct clock_ {
  18     DCPU16_WORD cycle_;
  19     DCPU16_WORD rate;
  20     DCPU16_WORD tick;
  21     DCPU16_WORD interrupt_message;
  22 };
  23
  24 static
  25 void clock_reset_(struct dcpu16 *vm, struct dcpu16_hw *hw) {
  26     struct clock_ *clock = (struct clock_ *)hw->data;
  27
  28     (void)vm;
  29
  30     memset(clock, 0, sizeof *clock);
  31 }
  32
  33 static
  34 void clock_cycle_(struct dcpu16 *vm, struct dcpu16_hw *hw) {
  35     struct clock_ *clock = (struct clock_ *)hw->data;
  36
  37     /* cycle is only called 100000 times per second */
  38     /* maximum rate is 60hz / word_max = 3932160 */
  39
  40     if (clock->rate == 0)
  41         return;
  42
  43     clock->cycle_++;
  44     if (clock->cycle_ >= clock->rate) {
  45         /* THIS CHECK IS WRONG, JUST A PLACEHOLDER */
  46         clock->cycle_ = 0;
  47         clock->tick += 1;
  48
  49         if (clock->interrupt_message) {
  50             if (dcpu16_interrupt(vm, clock->interrupt_message))
  51                 MSG_ERROR(vm, "%s: could not send interrupt", hw->mod->name_);
  52         }
  53     }
  54 }
  55
  56 static
  57 void clock_hwi_(struct dcpu16 *vm, struct dcpu16_hw *hw) {
  58     struct clock_ *clock = (struct clock_ *)hw->data;
  59     DCPU16_WORD reg_a = vm->reg[DCPU16_REG_A];
  60     DCPU16_WORD reg_b = vm->reg[DCPU16_REG_B];
  61
  62     switch (reg_a) {
  63         case 0: /* set tick gather rate, 60hz/B */
  64             clock->rate = reg_b;
  65             break;
  66
  67         case 1: /* fetch elapsed count since rate was set */
  68             vm->reg[DCPU16_REG_C] = clock->tick;
  69             break;
  70
  71         case 2:
  72             clock->interrupt_message = reg_b;
  73             break;
  74     }
  75 }
  76
  77 static
  78 int clock_data_init_(struct dcpu16_hw *hw, void *data) {
  79     (void)data;
  80
  81     hw->data = calloc(1, sizeof(struct clock_));
  82     if (hw->data == NULL) {
  83         MSG_ERROR(hw->vm, "%s():%s", "calloc", strerror(errno));
  84         return -1;
  85     }
  86     return 0;
  87 }
  88
  89 static
  90 void clock_data_free_(struct dcpu16_hw *hw) {
  91     if (hw) {
  92         if (hw->data) {
  93             free(hw->data);
  94             hw->data = NULL;
  95         }
  96     }
  97 }
  98
  99
 100 struct dcpu16_hw_module dcpu16_hw_module_clock = {
 101     .name_  = "Generic Clock (compatible)",
 102
 103     .id_l   = 0xb402,
 104     .id_h   = 0x12d0,
 105     .ver    = 0x0001,
 106     .mfg_l  = 0x0000,
 107     .mfg_h  = 0x0000,
 108     .hwi    = clock_hwi_,
 109     .cycle  = clock_cycle_,
 110     .reset  = clock_reset_,
 111
 112     .data_init = clock_data_init_,
 113     .data_free = clock_data_free_,
 114     .ctl = NULL,
 115     .ctl_cmd = NULL,
 116 };