chip8

commit 934636d6f440f339294b052a15024ce8bcb31e3b
parent b03a879d31f31a5f47590c693a01fbdd2f85367c
Author: Christos Margiolis <christos@margiolis.net>
Date:   Tue,  1 Sep 2020 21:31:51 +0300

minor changes

Diffstat:
M
src/chip8.c
 | 
23
++++-------------------
M
src/chip8.h
 | 
2
--
M
src/main.c
 | 
39
++++++++++++++++-----------------------

3 files changed, 20 insertions(+), 44 deletions(-)
diff --git a/src/chip8.c b/src/chip8.c
@@ -34,14 +34,12 @@ chip8_init(Chip8 *chip8)
         0xF0, 0x80, 0xF0, 0x80, 0xF0, // E
         0xF0, 0x80, 0xF0, 0x80, 0x80  // F
     };
-
     pc         = 0x200;
     opcode     = 0;
     I          = 0;
     sp         = 0;
     delaytimer = 0;
     soundtimer = 0;
-
     memset(V,      0, 16   * sizeof(uint8_t));
     memset(keys,   0, 16   * sizeof(uint8_t));
     memset(stack,  0, 16   * sizeof(uint16_t));
@@ -96,28 +94,22 @@ chip8_rom_load(Chip8 *chip8, const char *fpath)
 void
 chip8_emulate(Chip8 *chip8)
 {
-    chip8_fetch(chip8);
+    opcode = memory[pc] << 8 | memory[pc + 1]; // fetch
     if (chip8_decode(chip8))
     {
-        chip8_execute(chip8);
+        pc += 2; // execute
         chip8_timers_update(chip8);
     }
-    printf("opcode: %x\tmemory: %x\tI: %x\tsp: %x\tpc: %d\n",
+    printf("Opcode: %x\tMemory: %x\tI: %x\tSP: %x\tPC: %d\n",
             opcode, memory[pc] << 8 | memory[pc + 1], I, sp, pc);
 }
 
-void
-chip8_fetch(Chip8 *chip8)
-{
-    opcode = memory[pc] << 8 | memory[pc + 1];
-}
-
 int
 chip8_decode(Chip8 *chip8)
 {
-    int i;
     switch (opcode & 0xF000)
     {
+        int i;
         case 0x0000: // 00E_
             switch (opcode & 0x00FF)
             {
@@ -228,7 +220,6 @@ chip8_decode(Chip8 *chip8)
                     }
                 }
             }
-
             drawflag = TRUE;
         }
             break;
@@ -307,12 +298,6 @@ chip8_decode(Chip8 *chip8)
 }
 
 void
-chip8_execute(Chip8 *chip8)
-{
-    pc += 2;
-}
-
-void
 chip8_timers_update(Chip8 *chip8)
 {
     if (delaytimer > 0) --delaytimer;
diff --git a/src/chip8.h b/src/chip8.h
@@ -30,9 +30,7 @@ extern Chip8 chip8;
 extern void  chip8_init(Chip8 *chip8);
 extern int   chip8_rom_load(Chip8 *chip8, const char *fpath);
 extern void  chip8_emulate(Chip8 *chip8);
-extern void  chip8_fetch(Chip8 *chip8);
 extern int   chip8_decode(Chip8 *chip8);
-extern void  chip8_execute(Chip8 *chip8);
 extern void  chip8_timers_update(Chip8 *chip8);
 
 #endif /* CHIP8_H */
diff --git a/src/main.c b/src/main.c
@@ -17,14 +17,11 @@ evts(Chip8 *chip8)
     SDL_Event e;
     while (SDL_PollEvent(&e))
     {
-        if (e.type == SDL_QUIT) return FALSE; 
+        if (e.type == SDL_QUIT || e.key.keysym.sym == SDLK_ESCAPE) return FALSE; 
         if (e.type == SDL_KEYDOWN)
-        {
-            if (e.key.keysym.sym == SDLK_ESCAPE) return FALSE;
             for (i = 0; i < 16; i++)
                 if (e.key.keysym.sym == keymap[i])
                     chip8->keys[i] = TRUE;
-        }
         if (e.type == SDL_KEYUP)
             for (i = 0; i < 16; i++)
                 if (e.key.keysym.sym == keymap[i])
@@ -34,7 +31,7 @@ evts(Chip8 *chip8)
 }
 
 static void
-render(SDL_Renderer *r, SDL_Texture *t, Chip8 *chip8)
+render(SDL_Renderer *ren, SDL_Texture *tex, Chip8 *chip8)
 {
     int i;
     uint32_t pixels[2048];
@@ -44,16 +41,15 @@ render(SDL_Renderer *r, SDL_Texture *t, Chip8 *chip8)
         uint8_t pixel = chip8->gfx[i];
         pixels[i] = (0x00FFFFFF * pixel) | 0xFF000000;
     }
-    SDL_UpdateTexture(t, NULL, pixels, 64 * sizeof(Uint32));
-    SDL_RenderClear(r);
-    SDL_RenderCopy(r, t, NULL, NULL);
-    SDL_RenderPresent(r);
+    SDL_UpdateTexture(tex, NULL, pixels, 64 * sizeof(Uint32));
+    SDL_RenderClear(ren);
+    SDL_RenderCopy(ren, tex, NULL, NULL);
+    SDL_RenderPresent(ren);
 }
 
 int
 main(int argc, char **argv)
 {
-    SDL_Window *win = NULL;
     int w = 1024, h = 512;
     srand(time(NULL));
 
@@ -67,33 +63,30 @@ main(int argc, char **argv)
         fprintf(stderr, "Cannot initialize SDL. Exiting. . .\n");
         return EXIT_FAILURE;
     }
-
-    win = SDL_CreateWindow("CHIP-8 Emulator", SDL_WINDOWPOS_UNDEFINED,
+    SDL_Window *win = SDL_CreateWindow("CHIP-8 Emulator", SDL_WINDOWPOS_UNDEFINED,
                             SDL_WINDOWPOS_UNDEFINED, w, h,
                             SDL_WINDOW_SHOWN);
-    if (win == NULL)
+    SDL_Renderer *ren = SDL_CreateRenderer(win, -1, 0);
+    SDL_RenderSetLogicalSize(ren, w, h);
+    SDL_Texture *tex = SDL_CreateTexture(ren, SDL_PIXELFORMAT_ARGB8888,
+            SDL_TEXTUREACCESS_STREAMING, 64, 32);
+    if (!win || !ren || !tex)
     {
-        fprintf(stderr, "Cannot create SDL window. Exiting. . .\n%s\n", SDL_GetError());
+        fprintf(stderr, "SDL error. Exiting. . .\n%s\n", SDL_GetError());
         return EXIT_FAILURE;
     }
 
-    SDL_Renderer *renderer = SDL_CreateRenderer(win, -1, 0);
-    SDL_RenderSetLogicalSize(renderer, w, h);
-    SDL_Texture *texture = SDL_CreateTexture(
-            renderer, SDL_PIXELFORMAT_ARGB8888,
-            SDL_TEXTUREACCESS_STREAMING, 64, 32);
-
     Chip8 chip8;
     chip8_init(&chip8);
     if (!chip8_rom_load(&chip8, argv[1])) return EXIT_FAILURE;
     for (; evts(&chip8); usleep(1500))
     {
         chip8_emulate(&chip8);
-        if (chip8.drawflag) render(renderer, texture, &chip8);
+        if (chip8.drawflag) render(ren, tex, &chip8);
     }
 
-    SDL_DestroyTexture(texture);
-    SDL_DestroyRenderer(renderer);
+    SDL_DestroyTexture(tex);
+    SDL_DestroyRenderer(ren);
     SDL_DestroyWindow(win);
     SDL_Quit();
     return EXIT_SUCCESS;