Wed, 13 Mar 2013 01:10:34 +0000
merge changes from default
1 #include <stdio.h>
2 #include <stdlib.h>
3 #include <stdint.h>
4 #include <stdbool.h>
5 #include <malloc.h>
6 #include <string.h>
8 #include "SDL.h"
10 #include "musashi/m68k.h"
11 #include "version.h"
12 #include "state.h"
13 #include "memory.h"
15 void FAIL(char *err)
16 {
17 state_done();
18 fprintf(stderr, "ERROR: %s\nExiting...\n", err);
19 exit(EXIT_FAILURE);
20 }
22 static int load_fd()
23 {
25 int writeable = 1;
26 state.fdc_disc = fopen("discim", "r+b");
27 if (!state.fdc_disc){
28 writeable = 0;
29 state.fdc_disc = fopen("discim", "rb");
30 }
31 if (!state.fdc_disc){
32 fprintf(stderr, "ERROR loading disc image 'discim'.\n");
33 state.fdc_disc = NULL;
34 return (0);
35 }else{
36 wd2797_load(&state.fdc_ctx, state.fdc_disc, 512, 10, 2, writeable);
37 fprintf(stderr, "Disc image loaded.\n");
38 return (1);
39 }
40 }
42 static int load_hd()
43 {
45 state.hdc_disc0 = fopen("hd.img", "r+b");
46 if (!state.hdc_disc0){
47 fprintf(stderr, "ERROR loading disc image 'hd.img'.\n");
48 state.hdc_disc0 = NULL;
49 return (0);
50 }else{
51 wd2010_init(&state.hdc_ctx, state.hdc_disc0, 512, 16, 8);
52 fprintf(stderr, "Disc image loaded.\n");
53 return (1);
54 }
55 }
59 /**
60 * @brief Set the pixel at (x, y) to the given value
61 * @note The surface must be locked before calling this!
62 * @param surface SDL surface upon which to draw
63 * @param x X co-ordinate
64 * @param y Y co-ordinate
65 * @param pixel Pixel value (from SDL_MapRGB)
66 */
67 void putpixel(SDL_Surface *surface, int x, int y, Uint32 pixel)
68 {
69 int bpp = surface->format->BytesPerPixel;
70 /* Here p is the address to the pixel we want to set */
71 Uint8 *p = (Uint8 *)surface->pixels + y * surface->pitch + x * bpp;
73 switch (bpp) {
74 case 1:
75 *p = pixel;
76 break;
78 case 2:
79 *(Uint16 *)p = pixel;
80 break;
82 case 3:
83 if (SDL_BYTEORDER == SDL_BIG_ENDIAN) {
84 p[0] = (pixel >> 16) & 0xff;
85 p[1] = (pixel >> 8) & 0xff;
86 p[2] = pixel & 0xff;
87 }
88 else {
89 p[0] = pixel & 0xff;
90 p[1] = (pixel >> 8) & 0xff;
91 p[2] = (pixel >> 16) & 0xff;
92 }
93 break;
95 case 4:
96 *(Uint32 *)p = pixel;
97 break;
99 default:
100 break; /* shouldn't happen, but avoids warnings */
101 } // switch
102 }
105 /**
106 * @brief Refresh the screen.
107 * @param surface SDL surface upon which to draw.
108 */
109 void refreshScreen(SDL_Surface *s)
110 {
111 // Lock the screen surface (if necessary)
112 if (SDL_MUSTLOCK(s)) {
113 if (SDL_LockSurface(s) < 0) {
114 fprintf(stderr, "ERROR: Unable to lock screen!\n");
115 exit(EXIT_FAILURE);
116 }
117 }
119 // Map the foreground and background colours
120 Uint32 fg = SDL_MapRGB(s->format, 0x00, 0xFF, 0x00); // green foreground
121 // Uint32 fg = SDL_MapRGB(s->format, 0xFF, 0xC1, 0x06); // amber foreground
122 // Uint32 fg = SDL_MapRGB(s->format, 0xFF, 0xFF, 0xFF); // white foreground
123 Uint32 bg = SDL_MapRGB(s->format, 0x00, 0x00, 0x00); // black background
125 // Refresh the 3B1 screen area first. TODO: only do this if VRAM has actually changed!
126 uint32_t vram_address = 0;
127 for (int y=0; y<348; y++) {
128 for (int x=0; x<720; x+=16) { // 720 pixels, monochrome, packed into 16bit words
129 // Get the pixel
130 uint16_t val = RD16(state.vram, vram_address, sizeof(state.vram)-1);
131 vram_address += 2;
132 // Now copy it to the video buffer
133 for (int px=0; px<16; px++) {
134 if (val & 1)
135 putpixel(s, x+px, y, fg);
136 else
137 putpixel(s, x+px, y, bg);
138 val >>= 1;
139 }
140 }
141 }
143 // TODO: blit LEDs and status info
145 // Unlock the screen surface
146 if (SDL_MUSTLOCK(s)) {
147 SDL_UnlockSurface(s);
148 }
150 // Trigger a refresh -- TODO: partial refresh depending on whether we
151 // refreshed the screen area, status area, both, or none. Use SDL_UpdateRect() for this.
152 SDL_Flip(s);
153 }
155 /**
156 * @brief Handle events posted by SDL.
157 */
158 bool HandleSDLEvents(SDL_Surface *screen)
159 {
160 SDL_Event event;
161 while (SDL_PollEvent(&event))
162 {
163 if ((event.type == SDL_KEYDOWN) || (event.type == SDL_KEYUP)) {
164 keyboard_event(&state.kbd, &event);
165 }
167 switch (event.type) {
168 case SDL_QUIT:
169 // Quit button tagged. Exit.
170 return true;
171 case SDL_KEYDOWN:
172 switch (event.key.keysym.sym) {
173 case SDLK_F11:
174 if (state.fdc_disc) {
175 wd2797_unload(&state.fdc_ctx);
176 fclose(state.fdc_disc);
177 state.fdc_disc = NULL;
178 fprintf(stderr, "Disc image unloaded.\n");
179 } else {
180 load_fd();
181 }
182 break;
183 case SDLK_F12:
184 if (event.key.keysym.mod & (KMOD_LALT | KMOD_RALT))
185 // ALT-F12 pressed; exit emulator
186 return true;
187 break;
188 default:
189 break;
190 }
191 break;
192 default:
193 break;
194 }
195 }
197 return false;
198 }
201 /****************************
202 * blessed be thy main()...
203 ****************************/
205 int main(void)
206 {
207 // copyright banner
208 printf("FreeBee: A Quick-and-Dirty AT&T 3B1 Emulator. Version %s, %s mode.\n", VER_FULLSTR, VER_BUILD_TYPE);
209 printf("Copyright (C) 2010 P. A. Pemberton. All rights reserved.\nLicensed under the Apache License Version 2.0.\n");
210 printf("Musashi M680x0 emulator engine developed by Karl Stenerud <kstenerud@gmail.com>\n");
211 printf("Built %s by %s@%s.\n", VER_COMPILE_DATETIME, VER_COMPILE_BY, VER_COMPILE_HOST);
212 printf("Compiler: %s\n", VER_COMPILER);
213 printf("CFLAGS: %s\n", VER_CFLAGS);
214 printf("\n");
216 // set up system state
217 // 512K of RAM
218 int i;
219 if ((i = state_init(2048*1024, 2048*1024)) != STATE_E_OK) {
220 fprintf(stderr, "ERROR: Emulator initialisation failed. Error code %d.\n", i);
221 return i;
222 }
224 // set up musashi and reset the CPU
225 m68k_set_cpu_type(M68K_CPU_TYPE_68010);
226 m68k_pulse_reset();
228 // Set up SDL
229 if (SDL_Init(SDL_INIT_VIDEO | SDL_INIT_TIMER) == -1) {
230 printf("Could not initialise SDL: %s.\n", SDL_GetError());
231 exit(EXIT_FAILURE);
232 }
234 // Make sure SDL cleans up after itself
235 atexit(SDL_Quit);
237 // Set up the video display
238 SDL_Surface *screen = NULL;
239 if ((screen = SDL_SetVideoMode(720, 384, 8, SDL_SWSURFACE | SDL_ANYFORMAT)) == NULL) {
240 printf("Could not find a suitable video mode: %s.\n", SDL_GetError());
241 exit(EXIT_FAILURE);
242 }
243 printf("Set %dx%d at %d bits-per-pixel mode\n\n", screen->w, screen->h, screen->format->BitsPerPixel);
244 SDL_WM_SetCaption("FreeBee 3B1 emulator", "FreeBee");
246 // Load a disc image
247 load_fd();
249 load_hd();
251 /***
252 * The 3B1 CPU runs at 10MHz, with DMA running at 1MHz and video refreshing at
253 * around 60Hz (???), with a 60Hz periodic interrupt.
254 */
255 const uint32_t SYSTEM_CLOCK = 10e6; // Hz
256 const uint32_t TIMESLOT_FREQUENCY = 1000;//240; // Hz
257 const uint32_t MILLISECS_PER_TIMESLOT = 1e3 / TIMESLOT_FREQUENCY;
258 const uint32_t CLOCKS_PER_60HZ = (SYSTEM_CLOCK / 60);
259 uint32_t next_timeslot = SDL_GetTicks() + MILLISECS_PER_TIMESLOT;
260 uint32_t clock_cycles = 0, tmp;
261 bool exitEmu = false;
263 /*bool lastirq_fdc = false;*/
264 for (;;) {
265 // Run the CPU for however many cycles we need to. CPU core clock is
266 // 10MHz, and we're running at 240Hz/timeslot. Thus: 10e6/240 or
267 // 41667 cycles per timeslot.
268 tmp = m68k_execute(SYSTEM_CLOCK/TIMESLOT_FREQUENCY);
269 clock_cycles += tmp;
271 // Run the DMA engine
272 if (state.dmaen) {
273 // DMA ready to go -- so do it.
274 size_t num = 0;
275 while (state.dma_count < 0x4000) {
276 uint16_t d = 0;
277 // num tells us how many words we've copied. If this is greater than the per-timeslot DMA maximum, bail out!
278 if (num > (1e6/TIMESLOT_FREQUENCY)) break;
280 // Evidently we have more words to copy. Copy them.
281 if (state.fd_selected){
282 if (!wd2797_get_drq(&state.fdc_ctx)) {
283 // Bail out, no data available. Try again later.
284 break;
285 }
286 }else if (state.hd_selected){
287 if (!wd2010_get_drq(&state.hdc_ctx)) {
288 // Bail out, no data available. Try again later.
289 break;
290 }
291 }else{
292 printf("ERROR: DMA attempt with no drive selected!\n");
293 }
295 if (access_check_dma()) {
297 uint32_t newAddr;
298 // Map logical address to a physical RAM address
299 newAddr = MAP_ADDR(state.dma_address);
301 if (!state.dma_reading) {
302 // Data available. Get it from the FDC or HDC.
303 if (state.fd_selected) {
304 d = wd2797_read_reg(&state.fdc_ctx, WD2797_REG_DATA);
305 d <<= 8;
306 d += wd2797_read_reg(&state.fdc_ctx, WD2797_REG_DATA);
307 }else if (state.hd_selected) {
308 d = wd2010_read_data(&state.hdc_ctx);
309 d <<= 8;
310 d += wd2010_read_data(&state.hdc_ctx);
311 }
312 if (newAddr <= 0x1FFFFF) {
313 WR16(state.base_ram, newAddr, state.base_ram_size - 1, d);
314 } else if (newAddr >= 0x200000) {
315 WR16(state.exp_ram, newAddr - 0x200000, state.exp_ram_size - 1, d);
316 }
317 } else {
318 // Data write to FDC or HDC.
320 // Get the data from RAM
321 if (newAddr <= 0x1fffff) {
322 d = RD16(state.base_ram, newAddr, state.base_ram_size - 1);
323 } else {
324 if (newAddr <= (state.exp_ram_size + 0x200000 - 1))
325 d = RD16(state.exp_ram, newAddr - 0x200000, state.exp_ram_size - 1);
326 else
327 d = 0xffff;
328 }
330 // Send the data to the FDD or HDD
331 if (state.fd_selected){
332 wd2797_write_reg(&state.fdc_ctx, WD2797_REG_DATA, (d >> 8));
333 wd2797_write_reg(&state.fdc_ctx, WD2797_REG_DATA, (d & 0xff));
334 }else if (state.hd_selected){
335 wd2010_write_data(&state.hdc_ctx, (d >> 8));
336 wd2010_write_data(&state.hdc_ctx, (d & 0xff));
337 }
338 }
339 }
341 // Increment DMA address
342 state.dma_address+=2;
343 // Increment number of words transferred
344 num++; state.dma_count++;
345 }
347 // Turn off DMA engine if we finished this cycle
348 if (state.dma_count >= 0x4000) {
349 // FIXME? apparently this isn't required... or is it?
350 state.dma_count = 0x3fff;
351 /*state.dmaen = false;*/
352 }
353 }else if (wd2010_get_drq(&state.hdc_ctx)){
354 wd2010_dma_miss(&state.hdc_ctx);
355 }else if (wd2797_get_drq(&state.fdc_ctx)){
356 wd2797_dma_miss(&state.fdc_ctx);
357 }
360 // Any interrupts? --> TODO: masking
361 /* if (!lastirq_fdc) {
362 if (wd2797_get_irq(&state.fdc_ctx)) {
363 lastirq_fdc = true;
364 m68k_set_irq(2);
365 }
366 }
367 */
368 if (wd2797_get_irq(&state.fdc_ctx) || wd2010_get_irq(&state.hdc_ctx)) {
369 m68k_set_irq(2);
370 }else if (keyboard_get_irq(&state.kbd)) {
371 m68k_set_irq(3);
372 } else {
373 // if (!state.timer_asserted){
374 m68k_set_irq(0);
375 // }
376 }
378 // Is it time to run the 60Hz periodic interrupt yet?
379 if (clock_cycles > CLOCKS_PER_60HZ) {
380 // Refresh the screen
381 refreshScreen(screen);
382 if (state.timer_enabled){
383 m68k_set_irq(6);
384 state.timer_asserted = true;
385 }
386 // scan the keyboard
387 keyboard_scan(&state.kbd);
388 // decrement clock cycle counter, we've handled the intr.
389 clock_cycles -= CLOCKS_PER_60HZ;
390 }
392 // handle SDL events -- returns true if we need to exit
393 if (HandleSDLEvents(screen))
394 exitEmu = true;
396 // make sure frame rate is equal to real time
397 uint32_t now = SDL_GetTicks();
398 if (now < next_timeslot) {
399 // timeslot finished early -- eat up some time
400 SDL_Delay(next_timeslot - now);
401 } else {
402 // timeslot finished late -- skip ahead to gain time
403 // TODO: if this happens a lot, we should let the user know
404 // that their PC might not be fast enough...
405 next_timeslot = now;
406 }
407 // advance to the next timeslot
408 next_timeslot += MILLISECS_PER_TIMESLOT;
410 // if we've been asked to exit the emulator, then do so.
411 if (exitEmu) break;
412 }
414 // Release the disc image
415 wd2797_unload(&state.fdc_ctx);
416 fclose(state.fdc_disc);
418 return 0;
419 }