A xyw.c

@@ -0,0 +1,104 @@ 
+#include <stdio.h>
+
+typedef unsigned char xyw_byte;
+typedef unsigned short xyw_short;
+
+#define MEMORY_SIZE 0xffff
+#define STACK_SIZE 0xff
+#define DEVICE_AREA_START 0x0000
+#define SYSTEM_STACK_START 0x0100
+#define USER_STACK_START 0x0200
+#define USER_MEMORY_START 0x0300
+
+/* system device */
+#define SYSTEM_STATE 0x00
+#define SYSTEM_ERROR 0x01
+#define SYSTEM_SSP 0x02
+#define SYSTEM_USP 0x03
+#define SYSTEM_X 0x04
+#define SYSTEM_Y 0x05
+#define SYSTEM_XW 0x06
+#define SYSTEM_YW 0x08
+#define SYSTEM_PC 0x0A
+#define SYSTEM_ON_ERROR 0x0C
+
+/* console device */
+#define CONSOLE_BASE 0x10
+#define CONSOLE_INPUT 0x10
+#define CONSOLE_OUTPUT 0x11
+#define CONSOLE_ERROR 0x12
+#define CONSOLE_ON_KEYPRESS 0x13
+
+/* clock device */
+#define CLOCK_YEAR 0x20
+#define CLOCK_MONTH 0x22
+#define CLOCK_WEEK 0x23
+#define CLOCK_MONTHDAY 0x24
+#define CLOCK_WEEKDAY 0x25
+#define CLOCK_HOUR 0x26
+#define CLOCK_MINUTE 0x27
+#define CLOCK_SECOND 0x28
+#define CLOCK_TIMER 0x29
+#define CLOCK_ON_TIMER_ELAPSED 0x2B
+
+/* file device */
+#define FILE_PATH 0x30
+#define FILE_OPERATION 0x32
+#define FILE_STATE 0x33
+#define FILE_TYPE 0x34
+#define FILE_READ 0x35
+#define FILE_WRITE 0x36
+#define FILE_APPEND 0x37
+
+/* video device */
+#define VIDEO_WIDTH 0x40
+#define VIDEO_HEIGHT 0x41
+#define VIDEO_FILL 0x42
+#define VIDEO_X 0x43
+#define VIDEO_Y 0x44
+#define VIDEO_ON_RENDER 0x45
+
+/* audio device */
+#define AUDIO_STATE 0x50
+#define AUDIO_SAMPLES 0x51
+#define AUDIO_N_SAMPLES 0x53
+#define AUDIO_ON_STOP 0x55
+
+xyw_byte xyw_memory[MEMORY_SIZE];
+
+//// 1-byte pointers
+xyw_byte *ssp = &xyw_memory[SYSTEM_STACK_START];
+xyw_byte *usp = &xyw_memory[USER_STACK_START];
+xyw_byte *x = &xyw_memory[SYSTEM_X];
+xyw_byte *y = &xyw_memory[SYSTEM_Y];
+
+//// Helpers to manage 2-byte values to memory (big-endian)
+
+static inline xyw_short mget(xyw_short addr)
+{
+    return ((xyw_short)xyw_memory[addr] << 8) | xyw_memory[addr + 1];
+}
+
+static inline void mset(xyw_short addr, xyw_short val)
+{
+    xyw_memory[addr] = (val >> 8) & 0xFF;
+    xyw_memory[addr + 1] = val & 0xFF;
+}
+
+static inline void madd(xyw_short addr, int delta)
+{
+    xyw_short val = mget(addr);
+    mset(addr, (xyw_short)(val + delta));
+}
+
+//// Helpers for common registers
+
+static inline xyw_short pc(void) { return mget(SYSTEM_PC); }
+static inline void pc_set(xyw_short val) { mset(SYSTEM_PC, val); }
+static inline void pc_add(int delta) { madd(SYSTEM_PC, delta); }
+static inline xyw_short xw(void) { return mget(SYSTEM_XW); }
+static inline void xw_set(xyw_short val) { mset(SYSTEM_XW, val); }
+static inline void xw_add(int delta) { madd(SYSTEM_XW, delta); }
+static inline xyw_short yw(void) { return mget(SYSTEM_YW); }
+static inline void yw_set(xyw_short val) { mset(SYSTEM_YW, val); }
+static inline void yw_add(int delta) { madd(SYSTEM_YW, delta); }