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Basic handling of video/object processor register writes
author Michael Pavone <pavone@retrodev.com>
date Sat, 08 Oct 2016 23:49:20 -0700
parents 6433d4d05934
children 87597a048d38
comparison
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1087:6433d4d05934 1088:c0a026e974f4
1 #include <stdint.h> 1 #include <stdint.h>
2 #include <stdlib.h> 2 #include <stdlib.h>
3 #include <stdio.h>
3 #include "jag_video.h" 4 #include "jag_video.h"
5
6 enum {
7 VMODE_CRY,
8 VMODE_RGB24,
9 VMODE_DIRECT16,
10 VMODE_RGB16,
11 VMODE_VARIABLE
12 };
13
14 char *vmode_names[] = {
15 "CRY",
16 "RGB16",
17 "DIRECT16",
18 "VARIABLE"
19 };
4 20
5 jag_video *jag_video_init(void) 21 jag_video *jag_video_init(void)
6 { 22 {
7 return calloc(1, sizeof(jag_video)); 23 return calloc(1, sizeof(jag_video));
8 } 24 }
9 25
10 void jag_video_run(jag_video *context, uint32_t target_cycle) 26 void jag_video_run(jag_video *context, uint32_t target_cycle)
11 { 27 {
12 context->cycles = target_cycle; 28 context->cycles = target_cycle;
29
13 } 30 }
31
32 static uint8_t is_reg_writeable(uint32_t address)
33 {
34 return address < VID_HLPEN || address >= VID_OBJLIST1;
35 }
36
37 void jag_video_reg_write(jag_video *context, uint32_t address, uint16_t value)
38 {
39 uint32_t reg = (address >> 1 & 0x7F) - 2;
40 if (reg < JAG_VIDEO_REGS && is_reg_writeable(reg)) {
41 context->regs[reg] = value;
42 if (reg == VID_VMODE) {
43 context->pclock_div = (value >> 9 & 7) + 1;
44 context->pclock_counter = 0;
45 if (value & 0x10) {
46 context->mode = VMODE_VARIABLE;
47 } else {
48 context->mode = value >> 1 & 3;
49 }
50 printf("Mode %s, pixel clock divider: %d, time base generation: %s\n", vmode_names[context->mode], context->pclock_div, value & 1 ? "enabled" : "disabled");
51 }
52 switch (reg)
53 {
54 case VID_OBJLIST1:
55 printf("Object List Pointer 1: %X\n", value);
56 break;
57 case VID_OBJLIST2:
58 printf("Object List Pointer 2: %X\n", value);
59 break;
60 case VID_HPERIOD:
61 printf("Horizontal period: %d\n", value & 0x3FF);
62 break;
63 case VID_HBLANK_BEGIN:
64 printf("horizontal blanking begin: %d\n", value & 0x7FF);
65 break;
66 case VID_HBLANK_END:
67 printf("horizontal blanking end: %d\n", value & 0x7FF);
68 break;
69 case VID_HSYNC:
70 printf("horizontal sync start: %d\n", value & 0x7FF);
71 break;
72 case VID_HDISP_BEGIN1:
73 printf("horizontal display begin 1: %d\n", value & 0x7FF);
74 break;
75 case VID_HDISP_BEGIN2:
76 printf("horizontal display begin 2: %d\n", value & 0x7FF);
77 break;
78 case VID_HDISP_END:
79 printf("horizontal display end: %d\n", value & 0x7FF);
80 break;
81 case VID_VPERIOD:
82 printf("Vertical period: %d\n", value & 0x7FF);
83 break;
84 case VID_VBLANK_BEGIN:
85 printf("vertical blanking begin: %d\n", value & 0x7FF);
86 break;
87 case VID_VBLANK_END:
88 printf("vertical blanking end: %d\n", value & 0x7FF);
89 break;
90 case VID_VSYNC:
91 printf("vertical sync start: %d\n", value & 0x7FF);
92 break;
93 case VID_VDISP_BEGIN:
94 printf("vertical display begin: %d\n", value & 0x7FF);
95 break;
96 case VID_VDISP_END:
97 printf("vertical display end: %d\n", value & 0x7FF);
98 break;
99 }
100 } else {
101 fprintf(stderr, "Write to invalid video/object processor register %X:%X\n", address, value);
102 }
103 }