mirror of
https://github.com/sehugg/8bitworkshop.git
synced 2024-11-22 14:33:51 +00:00
165 lines
3.4 KiB
Plaintext
165 lines
3.4 KiB
Plaintext
#include <string.h>
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typedef unsigned char byte;
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typedef unsigned short word;
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// PLATFORM DEFINITION
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__sfr __at (0x0) input0;
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__sfr __at (0x1) input1;
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__sfr __at (0x2) input2;
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__sfr __at (0x3) input3;
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__sfr __at (0x1) ay8910_reg;
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__sfr __at (0x2) ay8910_data;
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__sfr __at (0x40) palette;
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byte __at (0xe000) cellram[28][32];
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byte __at (0xe800) tileram[256][8];
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#define LEFT1 !(input1 & 0x10)
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#define RIGHT1 !(input1 & 0x20)
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#define UP1 !(input1 & 0x40)
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#define DOWN1 !(input1 & 0x80)
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#define FIRE1 !(input2 & 0x20)
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#define COIN1 (input3 & 0x8)
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#define START1 !(input2 & 0x10)
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#define START2 !(input3 & 0x20)
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#define TIMER500HZ (input2 & 0x8)
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inline void set8910(byte reg, byte data) {
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ay8910_reg = reg;
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ay8910_data = data;
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}
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typedef enum {
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AY_PITCH_A_LO, AY_PITCH_A_HI,
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AY_PITCH_B_LO, AY_PITCH_B_HI,
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AY_PITCH_C_LO, AY_PITCH_C_HI,
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AY_NOISE_PERIOD,
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AY_ENABLE,
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AY_ENV_VOL_A,
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AY_ENV_VOL_B,
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AY_ENV_VOL_C,
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AY_ENV_PERI_LO, AY_ENV_PERI_HI,
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AY_ENV_SHAPE
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} AY8910Register;
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// STARTUP CODE
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void main();
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void gsinit();
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// start routine @ 0x0
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void start() {
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__asm
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LD SP,#0xE800 ; set up stack pointer
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DI ; disable interrupts
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__endasm;
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gsinit();
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main();
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}
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#define INIT_MAGIC 0xdeadbeef
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static long is_initialized = INIT_MAGIC;
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// set initialized portion of global memory
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// by copying INITIALIZER area -> INITIALIZED area
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void gsinit() {
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// already initialized? skip it
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if (is_initialized == INIT_MAGIC)
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return;
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__asm
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; copy initialized data to RAM
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LD BC, #l__INITIALIZER
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LD A, B
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LD DE, #s__INITIALIZED
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LD HL, #s__INITIALIZER
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LDIR
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__endasm;
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}
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// PLATFORM CODE
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static word lfsr = 1;
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word rand() {
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unsigned lsb = lfsr & 1; /* Get LSB (i.e., the output bit). */
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lfsr >>= 1; /* Shift register */
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if (lsb) { /* If the output bit is 1, apply toggle mask. */
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lfsr ^= 0xB400u;
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}
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return lfsr;
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}
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void delay(byte msec) {
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while (msec--) {
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while (TIMER500HZ != 0) lfsr++;
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while (TIMER500HZ == 0) lfsr++;
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}
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}
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#define PE(fg,bg) (((fg)<<5) | ((bg)<<1))
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const byte __at (0x4000) color_prom[32] = {
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PE(7,0),PE(3,0),PE(1,0),PE(3,0),PE(6,0),PE(3,0),PE(2,0),PE(6,0),
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PE(7,0),PE(3,0),PE(1,0),PE(3,0),PE(6,0),PE(3,0),PE(2,0),PE(6,0),
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PE(7,0),PE(3,0),PE(1,0),PE(3,0),PE(6,0),PE(3,0),PE(2,0),PE(6,0),
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PE(7,0),PE(3,0),PE(1,0),PE(3,0),PE(6,0),PE(3,0),PE(2,0),PE(6,0),
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};
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#define LOCHAR 0x0
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#define HICHAR 0xff
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#define CHAR(ch) (ch-LOCHAR)
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void clrscr() {
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memset(cellram, CHAR(' '), sizeof(cellram));
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}
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byte getchar(byte x, byte y) {
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return cellram[x][y];
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}
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void putchar(byte x, byte y, byte attr) {
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cellram[x][y] = attr;
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}
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void putstring(byte x, byte y, const char* string) {
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while (*string) {
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putchar(x++, y, CHAR(*string++));
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}
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}
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// PC font (code page 437)
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//#link "cp437.c"
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extern byte font8x8[0x100][8];
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const char BOX_CHARS[8] = { 218, 191, 192, 217, 196, 196, 179, 179 };
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void draw_box(byte x, byte y, byte x2, byte y2, const char* chars) {
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byte x1 = x;
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putchar(x, y, chars[2]);
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putchar(x2, y, chars[3]);
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putchar(x, y2, chars[0]);
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putchar(x2, y2, chars[1]);
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while (++x < x2) {
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putchar(x, y, chars[5]);
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putchar(x, y2, chars[4]);
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}
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while (++y < y2) {
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putchar(x1, y, chars[6]);
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putchar(x2, y, chars[7]);
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}
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}
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// GAME CODE
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void main() {
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palette = 0;
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memset(cellram, 0, sizeof(cellram));
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memcpy(tileram, font8x8, sizeof(font8x8));
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draw_box(0, 0, 27, 31, BOX_CHARS);
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while (1) ;
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}
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