Wed, 09 Feb 2011 22:05:42 +0000
merge heads
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 /**
23 * @brief Set the pixel at (x, y) to the given value
24 * @note The surface must be locked before calling this!
25 * @param surface SDL surface upon which to draw
26 * @param x X co-ordinate
27 * @param y Y co-ordinate
28 * @param pixel Pixel value (from SDL_MapRGB)
29 */
30 void putpixel(SDL_Surface *surface, int x, int y, Uint32 pixel)
31 {
32 int bpp = surface->format->BytesPerPixel;
33 /* Here p is the address to the pixel we want to set */
34 Uint8 *p = (Uint8 *)surface->pixels + y * surface->pitch + x * bpp;
36 switch (bpp) {
37 case 1:
38 *p = pixel;
39 break;
41 case 2:
42 *(Uint16 *)p = pixel;
43 break;
45 case 3:
46 if (SDL_BYTEORDER == SDL_BIG_ENDIAN) {
47 p[0] = (pixel >> 16) & 0xff;
48 p[1] = (pixel >> 8) & 0xff;
49 p[2] = pixel & 0xff;
50 }
51 else {
52 p[0] = pixel & 0xff;
53 p[1] = (pixel >> 8) & 0xff;
54 p[2] = (pixel >> 16) & 0xff;
55 }
56 break;
58 case 4:
59 *(Uint32 *)p = pixel;
60 break;
62 default:
63 break; /* shouldn't happen, but avoids warnings */
64 } // switch
65 }
68 /**
69 * @brief Refresh the screen.
70 * @param surface SDL surface upon which to draw.
71 */
72 void refreshScreen(SDL_Surface *s)
73 {
74 // Lock the screen surface (if necessary)
75 if (SDL_MUSTLOCK(s)) {
76 if (SDL_LockSurface(s) < 0) {
77 fprintf(stderr, "ERROR: Unable to lock screen!\n");
78 exit(EXIT_FAILURE);
79 }
80 }
82 // Map the foreground and background colours
83 Uint32 fg = SDL_MapRGB(s->format, 0x00, 0xFF, 0x00); // green foreground
84 // Uint32 fg = SDL_MapRGB(s->format, 0xFF, 0xC1, 0x06); // amber foreground
85 // Uint32 fg = SDL_MapRGB(s->format, 0xFF, 0xFF, 0xFF); // white foreground
86 Uint32 bg = SDL_MapRGB(s->format, 0x00, 0x00, 0x00); // black background
88 // Refresh the 3B1 screen area first. TODO: only do this if VRAM has actually changed!
89 uint32_t vram_address = 0;
90 for (int y=0; y<348; y++) {
91 for (int x=0; x<720; x+=16) { // 720 pixels, monochrome, packed into 16bit words
92 // Get the pixel
93 uint16_t val = RD16(state.vram, vram_address, sizeof(state.vram)-1);
94 vram_address += 2;
95 // Now copy it to the video buffer
96 for (int px=0; px<16; px++) {
97 if (val & 1)
98 putpixel(s, x+px, y, fg);
99 else
100 putpixel(s, x+px, y, bg);
101 val >>= 1;
102 }
103 }
104 }
106 // TODO: blit LEDs and status info
108 // Unlock the screen surface
109 if (SDL_MUSTLOCK(s)) {
110 SDL_UnlockSurface(s);
111 }
113 // Trigger a refresh -- TODO: partial refresh depending on whether we
114 // refreshed the screen area, status area, both, or none. Use SDL_UpdateRect() for this.
115 SDL_Flip(s);
116 }
118 /**
119 * @brief Handle events posted by SDL.
120 */
121 bool HandleSDLEvents(SDL_Surface *screen)
122 {
123 SDL_Event event;
124 while (SDL_PollEvent(&event))
125 {
126 if ((event.type == SDL_KEYDOWN) || (event.type == SDL_KEYUP)) {
127 keyboard_event(&state.kbd, &event);
128 }
130 switch (event.type) {
131 case SDL_QUIT:
132 // Quit button tagged. Exit.
133 return true;
134 case SDL_KEYDOWN:
135 switch (event.key.keysym.sym) {
136 case SDLK_F12:
137 if (event.key.keysym.mod & (KMOD_LALT | KMOD_RALT))
138 // ALT-F12 pressed; exit emulator
139 return true;
140 break;
141 default:
142 break;
143 }
144 break;
145 default:
146 break;
147 }
148 }
150 return false;
151 }
154 /****************************
155 * blessed be thy main()...
156 ****************************/
158 int main(void)
159 {
160 // copyright banner
161 printf("FreeBee: A Quick-and-Dirty AT&T 3B1 Emulator. Version %s, %s mode.\n", VER_FULLSTR, VER_BUILD_TYPE);
162 printf("Copyright (C) 2010 P. A. Pemberton. All rights reserved.\nLicensed under the Apache License Version 2.0.\n");
163 printf("Musashi M680x0 emulator engine developed by Karl Stenerud <kstenerud@gmail.com>\n");
164 printf("Built %s by %s@%s.\n", VER_COMPILE_DATETIME, VER_COMPILE_BY, VER_COMPILE_HOST);
165 printf("Compiler: %s\n", VER_COMPILER);
166 printf("CFLAGS: %s\n", VER_CFLAGS);
167 printf("\n");
169 // set up system state
170 // 512K of RAM
171 int i;
172 if ((i = state_init(512*1024, 512*1024)) != STATE_E_OK) {
173 fprintf(stderr, "ERROR: Emulator initialisation failed. Error code %d.\n", i);
174 return i;
175 }
177 // set up musashi and reset the CPU
178 m68k_set_cpu_type(M68K_CPU_TYPE_68010);
179 m68k_pulse_reset();
181 // Set up SDL
182 if (SDL_Init(SDL_INIT_VIDEO | SDL_INIT_TIMER) == -1) {
183 printf("Could not initialise SDL: %s.\n", SDL_GetError());
184 exit(EXIT_FAILURE);
185 }
187 // Make sure SDL cleans up after itself
188 atexit(SDL_Quit);
190 // Set up the video display
191 SDL_Surface *screen = NULL;
192 if ((screen = SDL_SetVideoMode(720, 384, 8, SDL_SWSURFACE | SDL_ANYFORMAT)) == NULL) {
193 printf("Could not find a suitable video mode: %s.\n", SDL_GetError());
194 exit(EXIT_FAILURE);
195 }
196 printf("Set %dx%d at %d bits-per-pixel mode\n\n", screen->w, screen->h, screen->format->BitsPerPixel);
197 SDL_WM_SetCaption("FreeBee 3B1 emulator", "FreeBee");
199 // Load a disc image
200 FILE *disc = fopen("discim", "rb");
201 if (!disc) {
202 fprintf(stderr, "ERROR loading disc image 'discim'.\n");
203 return -4;
204 }
205 wd2797_load(&state.fdc_ctx, disc, 512, 10, 2);
207 /***
208 * The 3B1 CPU runs at 10MHz, with DMA running at 1MHz and video refreshing at
209 * around 60Hz (???), with a 60Hz periodic interrupt.
210 */
211 const uint32_t TIMESLOT_FREQUENCY = 1000;//240; // Hz
212 const uint32_t MILLISECS_PER_TIMESLOT = 1e3 / TIMESLOT_FREQUENCY;
213 const uint32_t CLOCKS_PER_60HZ = (10e6 / 60);
214 uint32_t next_timeslot = SDL_GetTicks() + MILLISECS_PER_TIMESLOT;
215 uint32_t clock_cycles = 0;
216 bool exitEmu = false;
217 bool lastirq_fdc = false;
218 for (;;) {
219 // Run the CPU for however many cycles we need to. CPU core clock is
220 // 10MHz, and we're running at 240Hz/timeslot. Thus: 10e6/240 or
221 // 41667 cycles per timeslot.
222 clock_cycles += m68k_execute(10e6/TIMESLOT_FREQUENCY);
224 // Run the DMA engine
225 if (state.dmaen) {
226 // DMA ready to go -- so do it.
227 size_t num = 0;
228 while (state.dma_count < 0x4000) {
229 uint16_t d = 0;
231 // num tells us how many words we've copied. If this is greater than the per-timeslot DMA maximum, bail out!
232 if (num > (1e6/TIMESLOT_FREQUENCY)) break;
234 // Evidently we have more words to copy. Copy them.
235 if (!wd2797_get_drq(&state.fdc_ctx)) {
236 // Bail out, no data available. Try again later.
237 // TODO: handle HDD controller too
238 break;
239 }
241 // Check memory access permissions
242 // TODO: enforce these!!!! use ACCESS_CHECK_* for guidance.
243 bool access_ok;
244 switch (checkMemoryAccess(state.dma_address, !state.dma_reading)) {
245 case MEM_PAGEFAULT:
246 // Page fault
247 state.genstat = 0x8BFF
248 | (state.dma_reading ? 0x4000 : 0)
249 | (state.pie ? 0x0400 : 0);
250 access_ok = false;
251 break;
253 case MEM_UIE:
254 // User access to memory above 4MB
255 // FIXME? Shouldn't be possible with DMA... assert this?
256 state.genstat = 0x9AFF
257 | (state.dma_reading ? 0x4000 : 0)
258 | (state.pie ? 0x0400 : 0);
259 access_ok = false;
260 break;
262 case MEM_KERNEL:
263 case MEM_PAGE_NO_WE:
264 // Kernel access or page not write enabled
265 access_ok = false;
266 break;
268 case MEM_ALLOWED:
269 access_ok = true;
270 break;
271 }
272 if (!access_ok) {
273 state.bsr0 = 0x3C00;
274 state.bsr0 |= (state.dma_address >> 16);
275 state.bsr1 = state.dma_address & 0xffff;
276 m68k_pulse_bus_error();
277 printf("BUS ERROR FROM DMA: genstat=%04X, bsr0=%04X, bsr1=%04X\n", state.genstat, state.bsr0, state.bsr1);
279 // TODO: FIXME: if we get a pagefault, it NEEDS to be tagged as 'peripheral sourced'... this is a HACK!
280 printf("REALLY BIG FSCKING HUGE ERROR: DMA Memory Access caused a FAULT!\n");
281 exit(-1);
282 }
284 // Map logical address to a physical RAM address
285 uint32_t newAddr = mapAddr(state.dma_address, !state.dma_reading);
287 if (!state.dma_reading) {
288 // Data available. Get it from the FDC. TODO: handle HDD too
289 d = wd2797_read_reg(&state.fdc_ctx, WD2797_REG_DATA);
290 d <<= 8;
291 d += wd2797_read_reg(&state.fdc_ctx, WD2797_REG_DATA);
293 if (newAddr <= 0x1FFFFF) {
294 WR16(state.base_ram, newAddr, state.base_ram_size - 1, d);
295 } else if (newAddr >= 0x200000) {
296 WR16(state.exp_ram, newAddr - 0x200000, state.exp_ram_size - 1, d);
297 }
298 m68k_write_memory_16(state.dma_address, d);
299 } else {
300 // Data write to FDC. TODO: handle HDD too.
302 // Get the data from RAM
303 if (newAddr <= 0x1fffff) {
304 d = RD16(state.base_ram, newAddr, state.base_ram_size - 1);
305 } else {
306 if (newAddr <= (state.exp_ram_size + 0x200000 - 1))
307 d = RD16(state.exp_ram, newAddr - 0x200000, state.exp_ram_size - 1);
308 else
309 d = 0xffff;
310 }
312 // Send the data to the FDD
313 wd2797_write_reg(&state.fdc_ctx, WD2797_REG_DATA, (d >> 8));
314 wd2797_write_reg(&state.fdc_ctx, WD2797_REG_DATA, (d & 0xff));
315 }
317 // Increment DMA address
318 state.dma_address+=2;
319 // Increment number of words transferred
320 num++; state.dma_count++;
321 }
323 // Turn off DMA engine if we finished this cycle
324 if (state.dma_count >= 0x4000) {
325 // FIXME? apparently this isn't required... or is it?
326 // state.dma_count = 0;
327 state.dmaen = false;
328 }
329 }
331 // Any interrupts? --> TODO: masking
332 /* if (!lastirq_fdc) {
333 if (wd2797_get_irq(&state.fdc_ctx)) {
334 lastirq_fdc = true;
335 m68k_set_irq(2);
336 } else {
337 lastirq_fdc = false;
338 }
339 */ if (keyboard_get_irq(&state.kbd)) {
340 // TODO: this is a LEVEL, not an EDGE!
341 m68k_set_irq(3);
342 } else {
343 lastirq_fdc = wd2797_get_irq(&state.fdc_ctx);
344 m68k_set_irq(0);
345 }
347 // Is it time to run the 60Hz periodic interrupt yet?
348 if (clock_cycles > CLOCKS_PER_60HZ) {
349 // Refresh the screen
350 refreshScreen(screen);
351 // TODO: trigger periodic interrupt (if enabled)
352 // scan the keyboard
353 keyboard_scan(&state.kbd);
354 // decrement clock cycle counter, we've handled the intr.
355 clock_cycles -= CLOCKS_PER_60HZ;
356 }
358 // handle SDL events -- returns true if we need to exit
359 if (HandleSDLEvents(screen))
360 exitEmu = true;
362 // make sure frame rate is equal to real time
363 uint32_t now = SDL_GetTicks();
364 if (now < next_timeslot) {
365 // timeslot finished early -- eat up some time
366 SDL_Delay(next_timeslot - now);
367 } else {
368 // timeslot finished late -- skip ahead to gain time
369 // TODO: if this happens a lot, we should let the user know
370 // that their PC might not be fast enough...
371 next_timeslot = now;
372 }
373 // advance to the next timeslot
374 next_timeslot += MILLISECS_PER_TIMESLOT;
376 // if we've been asked to exit the emulator, then do so.
377 if (exitEmu) break;
378 }
380 // Release the disc image
381 wd2797_unload(&state.fdc_ctx);
382 fclose(disc);
384 return 0;
385 }