A devices/system.c

@@ -0,0 +1,25 @@ 
+#include "../xyw.h"
+
+xyw_byte system_read(xyw_byte *data, xyw_byte addr, xyw_byte *error)
+{
+    (void)error;
+    return data[addr];
+}
+
+void system_write(xyw_byte *data, xyw_byte addr, xyw_byte val, xyw_byte *error)
+{
+    (void)error;
+    data[addr] = val;
+}
+
+xyw_word system_readw(xyw_byte *data, xyw_byte addr, xyw_byte *error)
+{
+    (void)error;
+    return XYW_PEEKW(&data[addr]);
+}
+
+void system_writew(xyw_byte *data, xyw_byte addr, xyw_word val, xyw_byte *error)
+{
+    (void)error;
+    XYW_POKEW(&data[addr], val);
+}

M xyw.h → xyw.h

@@ -8,9 +8,24 @@ #define XYW_TOTAL_INSTRUCTIONS 0x20
 #define XYW_TOTAL_DEVICES 0x10
 
 // clang-format off
-#define PEEKW(d) (*(d) << 8 | (d)[1])
-#define POKEW(d, v) { *(d) = (v) >> 8; (d)[1] = (v); }
+#define XYW_PEEKW(d) (*(d) << 8 | (d)[1])
+#define XYW_POKEW(d, v) { *(d) = (v) >> 8; (d)[1] = (v); }
 // clang-format on
+
+/* system device */
+#define XYW_SYSTEM_STATE 0xff00
+#define XYW_SYSTEM_ERROR 0xff01
+#define XYW_SYSTEM_S 0xff02
+#define XYW_SYSTEM_U 0xff03
+#define XYW_SYSTEM_PAGE 0xff04
+#define XYW_SYSTEM_ON_ERROR 0xff05
+
+/* console device */
+#define XYW_CONSOLE_BASE 0xff10
+#define XYW_CONSOLE_INPUT 0xff10
+#define XYW_CONSOLE_OUTPUT 0xff11
+#define XYW_CONSOLE_ERROR 0xff12
+#define XYW_CONSOLE_ON_KEYPRESS 0xff13
 
 typedef unsigned char xyw_byte;
 typedef unsigned short xyw_word;

M xywrun.c → xywrun.c

@@ -1,6 +1,8 @@ 
 #include <stdio.h>
 #include "xyw.h"
 
+#include "devices/system.c"
+
 #define MEMORY_SIZE 0xffff
 #define STACK_SIZE 0xff
 
@@ -20,36 +22,21 @@ XYW_ERROR_DEVICE_UNAVAILABLE,
     XYW_ERROR_INVALID_DEVICE_PORT
 } xyw_error;
 
-/* system device */
-#define SYSTEM_STATE 0xff00
-#define SYSTEM_ERROR 0xff01
-#define SYSTEM_S 0xff02
-#define SYSTEM_U 0xff03
-#define SYSTEM_PAGE 0xff04
-#define SYSTEM_ON_ERROR 0xff05
-
-/* console device */
-#define CONSOLE_BASE 0xff10
-#define CONSOLE_INPUT 0xff10
-#define CONSOLE_OUTPUT 0xff11
-#define CONSOLE_ERROR 0xff12
-#define CONSOLE_ON_KEYPRESS 0xff13
-
 /// Main memory and stacks
 xyw_byte xyw_memory[MEMORY_SIZE];
 xyw_byte system_stack[STACK_SIZE];
 xyw_byte user_stack[STACK_SIZE];
 
-#define DIRECT_PAGE (xyw_memory[SYSTEM_PAGE] << 8)
+#define DIRECT_PAGE (xyw_memory[XYW_SYSTEM_PAGE] << 8)
 
 //// 1-byte pointers and registers
-xyw_byte *s = &xyw_memory[SYSTEM_S];
-xyw_byte *u = &xyw_memory[SYSTEM_U];
+xyw_byte *s = &xyw_memory[XYW_SYSTEM_S];
+xyw_byte *u = &xyw_memory[XYW_SYSTEM_U];
 static xyw_byte x_val = 0; // X register storage
 static xyw_byte y_val = 0; // Y register storage
 xyw_byte *x = &x_val;
 xyw_byte *y = &y_val;
-xyw_byte *error = &xyw_memory[SYSTEM_ERROR];
+xyw_byte *error = &xyw_memory[XYW_SYSTEM_ERROR];
 
 //// 2-byte registers
 static xyw_word pc_storage = 0; // Program counter storage
@@ -71,8 +58,8 @@ // Should return a number between 0 and 15, add validation
     xyw_byte port = (addr - DEVICE_AREA_START) % 16;
     if (port >= 16)
     {
-        *error = XYW_ERROR_INVALID_DEVICE_PORT;
-        return 0xFF;
+        *error = XYW_ERROR_DEVICE_UNAVAILABLE;
+        return -1;
     }
     return port;
 }
@@ -92,7 +79,7 @@ }
         xyw_byte dev_addr = get_device_port(addr);
         return xyw_devices[dev_num].readw(dev_addr, error);
     }
-    return PEEKW(&xyw_memory[addr]);
+    return XYW_PEEKW(&xyw_memory[addr]);
 }
 
 static inline void writew(xyw_word addr, xyw_word val)
@@ -109,7 +96,7 @@ xyw_byte dev_addr = get_device_port(addr);
         xyw_devices[dev_num].writew(dev_addr, val, error);
         return;
     }
-    POKEW(&xyw_memory[addr], val);
+    XYW_POKEW(&xyw_memory[addr], val);
 }
 
 static inline xyw_byte read(xyw_word addr)
@@ -153,7 +140,7 @@ static xyw_word ss_popw()
 {
     if (*s < 2)
     {
-        xyw_memory[SYSTEM_ERROR] = XYW_ERROR_STACK_UNDERFLOW;
+        xyw_memory[XYW_SYSTEM_ERROR] = XYW_ERROR_STACK_UNDERFLOW;
         return -1;
     }
     xyw_word val = readw(SYSTEM_STACK_START + (*s) - 2);
@@ -166,7 +153,7 @@ static void ss_pushw(xyw_word val)
 {
     if (*s > STACK_SIZE - 2)
     {
-        xyw_memory[SYSTEM_ERROR] = XYW_ERROR_STACK_OVERFLOW;
+        xyw_memory[XYW_SYSTEM_ERROR] = XYW_ERROR_STACK_OVERFLOW;
         return;
     }
     writew(SYSTEM_STACK_START + *s, val);
@@ -179,7 +166,7 @@ static void us_push(xyw_byte val)
 {
     if (*u > STACK_SIZE - 1)
     {
-        xyw_memory[SYSTEM_ERROR] = XYW_ERROR_STACK_OVERFLOW;
+        xyw_memory[XYW_SYSTEM_ERROR] = XYW_ERROR_STACK_OVERFLOW;
         return;
     }
     xyw_dbg(" => %02X\n", val);
@@ -190,7 +177,7 @@ static void us_pushw(xyw_word val)
 {
     if (*u > STACK_SIZE - 2)
     {
-        xyw_memory[SYSTEM_ERROR] = XYW_ERROR_STACK_OVERFLOW;
+        xyw_memory[XYW_SYSTEM_ERROR] = XYW_ERROR_STACK_OVERFLOW;
         return;
     }
     writew(USER_STACK_START + *u, val);
@@ -202,7 +189,7 @@ static xyw_byte us_pop()
 {
     if (*u < 1)
     {
-        xyw_memory[SYSTEM_ERROR] = XYW_ERROR_STACK_UNDERFLOW;
+        xyw_memory[XYW_SYSTEM_ERROR] = XYW_ERROR_STACK_UNDERFLOW;
         return -1;
     }
     (*u) -= 1;
@@ -215,7 +202,7 @@ static xyw_word us_popw()
 {
     if (*u < 2)
     {
-        xyw_memory[SYSTEM_ERROR] = XYW_ERROR_STACK_UNDERFLOW;
+        xyw_memory[XYW_SYSTEM_ERROR] = XYW_ERROR_STACK_UNDERFLOW;
         return -1;
     }
     xyw_word val = readw(USER_STACK_START + (*u) - 2);
@@ -351,8 +338,8 @@ return -1;
     }
     xyw_dbg("Loaded %zu bytes into memory\n", bytes_read);
     fclose(fp);
-    xyw_memory[SYSTEM_STATE] = 1;
-    while (xyw_memory[SYSTEM_STATE] && *pc < SYSTEM_MEMORY_START)
+    xyw_memory[XYW_SYSTEM_STATE] = 1;
+    while (xyw_memory[XYW_SYSTEM_STATE] && *pc < SYSTEM_MEMORY_START)
     {
         xyw_dbg("PC: %04X -> %02X (%s)\n", *pc, xyw_memory[*pc], xyw_instructions[xyw_memory[*pc] & 0x1F]);
         switch (xyw_memory[*pc])