memory layout revamp

equi.c

@@ -60,7 +60,7 @@
 
 /* Command buffer size in bytes */
 #ifndef GPD_AREA_SIZE
-#define GPD_AREA_SIZE 5100u
+#define GPD_AREA_SIZE 5000u
 #endif
 
 /* Command buffer size in bytes */
@@ -90,23 +90,27 @@ struct CLTEntry {
   ushort loc;   /* compiled word location */
 };
 
-struct EquiRAM { 
+struct EquiRAM {
+  ushort stack_size; /* main/return stack size in words */
+  uchar literal_stack_size; /* literal stack size in bytes */
+  uchar lsp; /* literal stack pointer */
+  ushort msp; /* main stack pointer */
+  ushort rsp; /* return stack pointer */
+  ushort clt_start; /* compilation lookup table start */
+  ushort gpd_start; /* GPD area start */
+  ushort cmd_start; /* command buffer start */
+  ushort cmd_size; /* command buffer size in bytes */
+  ushort pc; /* program counter */
+  ushort cbp; /* compilation buffer pointer */
+  ushort cltp; /* compilation lookup table pointer */
+  ushort ibp; /* input buffer pointer */
+  uchar II; /* instruction ignore mode flag */
+  uchar CM; /* compilation mode flag */
+  uchar IM; /* interpretation mode flag */
+  uchar MM; /* minification bypass mode flag */
   ushort main_stack[STACK_SIZE_WORDS];
   ushort return_stack[STACK_SIZE_WORDS];
   uchar literal_stack[LIT_STACK_SIZE];
-  ushort pc; /* program counter */
-  ushort msp; /* main stack pointer */
-  ushort rsp; /* return stack pointer */
-  uchar lsp; /* literal stack pointer */
-  ushort cbp; /* compilation buffer pointer */
-  ushort cltp; /* compilation lookup table pointer */
-  unsigned int II:1; /* instruction ignore mode */
-  unsigned int CM:1; /* compilation mode */
-  unsigned int IM:1; /* interpretation mode */
-  ushort gpd_start;
-  ushort cmd_start;
-  ushort cmd_size;
-  ushort ibp; /* input buffer pointer */
   struct CLTEntry clt[CLT_ENTRIES_MAX]; /* compilation lookup table */
   uchar gpd[GPD_AREA_SIZE];
   uchar cmdbuf[CMD_BUF_SIZE];
@@ -129,7 +133,8 @@ enum EquiErrors {
   INVALID_INSTRUCTION,
   INVALID_WORD,
   PORT_IO_ERROR,
-  PERSIST_IO_ERROR
+  PERSIST_IO_ERROR,
+  RESTRICTED_WRITE_ERROR
 };
 
 /* Error reporting method */
@@ -164,6 +169,9 @@ void trapout(errcode) {
       case PERSIST_IO_ERROR:
         cerr("Persistent storage I/O error\n");
         break;
+      case RESTRICTED_WRITE_ERROR:
+        cerr("Attempt to write to a restricted RAM area\n");
+        break;
     }
     exit(errcode);
   }
@@ -578,11 +586,7 @@ void equi_main_loop() {
 /* Equi VM entry point */
 
 int main(int argc, char* argv[]) {
-  uchar instr, bc, mmode = 0, smode = 0;
+  uchar instr, bc, smode = 0;
-  if(argc > 1 && argv[1][0] == 'm') /* enter minification mode, don't run the programs */
-    mmode = 1;
-  else if(argc > 1 && argv[1][0] == 's') /* enter silent mode, don't print the banners and prompts */
-    smode = 1;
   /* _attempt_ to disable buffering for char input/output */
 #if !defined __CC65__ && !defined __TINYC__
   setvbuf(stdin, NULL, _IONBF, 0);
@@ -591,27 +595,31 @@ int main(int argc, char* argv[]) {
   /* initialize the PRNG */
   srand((unsigned)time(NULL));
   /* initialize the RAM in the most standard way */
-  ram.gpd_start = (uchar *)&ram.gpd - (uchar *)&ram.main_stack;
+  ram.stack_size = STACK_SIZE_WORDS;
-  ram.cmd_start = (uchar *)&ram.cmdbuf - (uchar *)&ram.main_stack;
+  ram.literal_stack_size = LIT_STACK_SIZE;
+  ram.clt_start = (uchar *)&ram.clt - (uchar *)&ram.stack_size;
+  ram.gpd_start = (uchar *)&ram.gpd - (uchar *)&ram.stack_size;
+  ram.cmd_start = (uchar *)&ram.cmdbuf - (uchar *)&ram.stack_size;
   ram.cmd_size = CMD_BUF_SIZE;
-  ram.II = ram.CM = ram.IM = 0; /* reset all flags */
+  ram.II = ram.CM = ram.IM = ram.MM = 0; /* reset all flags */
+  /* process command line params */
+  if(argc > 1 && argv[1][0] == 'm') /* enter minification mode, don't run the programs */
+    ram.MM = 1;
+  else if(argc > 1 && argv[1][0] == 's') /* enter silent mode, don't print the banners and prompts */
+    smode = 1;
   /* Start both execution and input buffering from the start of command buffer (-1 because we use prefix increment) */
   ram.pc = ram.ibp = 65535U;
 
-  if(!mmode && !smode) { /* skip the terminal init and the greeting if in minification or silent mode */
+  if(!ram.MM && !smode) { /* skip the terminal init and the greeting if in minification or silent mode */
-  /* CC65-specific terminal init */
+    /* CC65-specific terminal init */
 #ifdef __CC65__
-  clrscr();
+    clrscr();
-  bc = cursor(1);
+    bc = cursor(1);
 #else /* VT100-compatible terminal init */
-  printf("\033c");
+    printf("\033c");
 #endif
-  printf("Welcome to Equi v" EQUI_VER " by Luxferre, 2022\nCLT: 0x%04X (%d bytes)\nGPD: 0x%04X (%d bytes)\nCommand buffer: 0x%04X (%d bytes)\nEqui ready\n\n> ",
+    printf("Welcome to Equi v" EQUI_VER " by Luxferre, 2022\nCLT: 0x%04X (%d bytes)\nGPD: 0x%04X (%d bytes)\nCommand buffer: 0x%04X (%d bytes)\nEqui ready\n\n> ",
-      (unsigned int) ((uchar *)&ram.clt - (uchar *)&ram.main_stack),
+      ram.clt_start, ram.gpd_start - ram.clt_start, ram.gpd_start, ram.cmd_start - ram.gpd_start, ram.cmd_start, ram.cmd_size);
-      (unsigned int) ((uchar *)&ram.gpd - (uchar *)&ram.clt),
-      ram.gpd_start,
-      ram.cmd_start - ram.gpd_start,
-      ram.cmd_start, ram.cmd_size);
   }
 
   while(1) { /* Now, we're in the command mode loop */
@@ -633,7 +641,7 @@ int main(int argc, char* argv[]) {
 #endif
       ram.II = 0;
     } else if(!ram.II && (instr == 0xFFU || instr == INS_QUIT)) { 
-      if(mmode) { /* output command buffer contents to stdout and exit */
+      if(ram.MM) { /* output command buffer contents to stdout and exit */
         ram.cmdbuf[++ram.ibp] = INS_QUIT; /* end program with INS_QUIT */
         ram.cmdbuf[++ram.ibp] = 0; /* and zero terminator */
         puts((const char *)&ram.cmdbuf[0]); /* output the command buffer */