Persistent operations implemented

equi.c

@@ -72,6 +72,11 @@
 #define CLT_ENTRIES_MAX 512u
 #endif
 
+/* Persistent storage sandbox file name */
+#ifndef PERSIST_FILE
+#define PERSIST_FILE "PERS.DAT"
+#endif
+
 /* Some necessary constants and offsets derived from the above values */
 #define STACK_SIZE_WORDS (STACK_SIZE / WS) /* Main and return stack size in words */
 
@@ -122,7 +127,8 @@ enum EquiErrors {
   CMD_OVERFLOW,
   INVALID_INSTRUCTION,
   INVALID_WORD,
-  PORT_IO_ERROR
+  PORT_IO_ERROR,
+  PERSIST_IO_ERROR
 };
 
 /* Error reporting method */
@@ -154,6 +160,9 @@ void trapout(errcode) {
       case PORT_IO_ERROR:
         cerr("Port I/O error\n");
         break;
+      case PERSIST_IO_ERROR:
+        cerr("Persistent storage I/O error\n");
+        break;
     }
     exit(errcode);
   }
@@ -296,13 +305,24 @@ ushort crc16(const uchar* data_p, uchar length) {
 
 /* Persistent operation handler */
 
-ushort persistOp(maddr, dataLen, adl, adh, isWrite) {
+ushort persistOp(FILE *pfd, ushort maddr, ushort dataLen, ushort adl, ushort adh, uchar isWrite) {
+  ushort status = 0, proc;
+  if(pfd) {
+    fseek(pfd, (adh << 16) | adl, SEEK_SET);
+    if(isWrite) /* writing to the persistent area from the memory */
+      proc = (ushort) fwrite(&flatram[maddr], 1, dataLen, pfd);
+    else /* reading from the persistent area into the memory */
+      proc = (ushort) fread(&flatram[maddr], 1, dataLen, pfd);
+    if(proc != dataLen)
+      status = PERSIST_IO_ERROR;
+  }
+  pushMain(status);
   return 0;
 }
 
 /* Port I/O handler */
 
-void portIO(port, p2, p1) {
+void portIO(ushort port, ushort p2, ushort p1) {
   ushort r1 = 0, r2 = 0, status = 0;
   switch(port) {
     case PORT_ECHO:
@@ -329,6 +349,8 @@ void portIO(port, p2, p1) {
 void equi_main_loop() {
   uchar instr;
   ushort lhash, pbuf, pbuf2;
+  /* try to open the persistent sandbox file */
+  FILE *pfd = fopen(PERSIST_FILE, "r+b");
   /* reset all stacks before running and reinit CLT */
   ram.msp = ram.rsp = ram.lsp = ram.cltp = 0;
   /* reset pc */
@@ -529,10 +551,10 @@ void equi_main_loop() {
         portIO(popMain(), popMain(), popMain());
         break;
       case INS_PERSIST_READ: /* ( adh adl len maddr -- status) */
-        pushMain(persistOp(popMain(), popMain(), popMain(), popMain(), 0));
+        pushMain(persistOp(pfd, popMain(), popMain(), popMain(), popMain(), 0));
         break;
       case INS_PERSIST_WRITE: /* ( adh adl len maddr -- status) */
-        pushMain(persistOp(popMain(), popMain(), popMain(), popMain(), 1));
+        pushMain(persistOp(pfd, popMain(), popMain(), popMain(), popMain(), 1));
         break;
       default: /* all characters not processed before are invalid instructions */
         trapout(INVALID_INSTRUCTION);
@@ -543,6 +565,8 @@ void equi_main_loop() {
     continue;
     brx: break;
   }
+  /* close the persistent sandbox file if open */
+  if(pfd) fclose(pfd);
   /* unset interpretation mode flag and exit */
   ram.IM = 0;
   ram.pc = ram.ibp = 65535U;