Yet another RAM structure revamp for memory protection and future multitasking - to be reflected in README

equi.c

@@ -101,6 +101,9 @@ struct EquiCtx { /* one Equi program context */
   ushort rsp; /* return stack pointer */
   ushort lsp; /* literal stack pointer */
   ushort cltp; /* compilation lookup table pointer */
+  ushort cbp; /* compilation buffer pointer */
+  uchar CM; /* compilation mode flag */
+  uchar IM; /* interpretation mode flag */
   ushort gpd_start; /* GPD area start for this task */
   ushort cmd_start; /* command buffer start for this task */
   ushort cmd_size; /* size of loaded code in bytes for this task */
@@ -117,11 +120,8 @@ struct EquiRAM {
   uchar literal_stack_size; /* literal stack size in bytes */
   ushort cmd_start; /* (global) command buffer start */
   ushort cmd_size; /* (global) command buffer size in bytes */
-  ushort cbp; /* compilation buffer 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 taskcount; /* count of active tasks */
   ushort taskid; /* currently running task ID - necessary? */
@@ -400,6 +400,8 @@ struct EquiCtx* equi_load_task(ushort progStart, ushort len) {
   taskptr->cmd_size = len; /* actual command buffer size */
   taskptr->id = ram.taskcount; /* assign task ID */
   taskptr->gpd_start = (ushort) (taskptr->gpd - flatram); /* assign GPD area start */
+  taskptr->IM = 1; /* set interpretation mode flag */
+  taskptr->CM = 0; /* unset compilation mode flag */
   ++ram.taskcount; /* increase task count */
   return taskptr;
 }
@@ -421,7 +423,7 @@ void equi_main_loop() {
       continue;
     }
     /* then, check for compilation mode */
-    if(ram.CM) {
+    if(curtask->CM) {
       if(instr == INS_CMEND) { /* trigger word compilation logic as per the spec */
         if(curtask->lsp < 1)
           trapout(STACK_UNDERFLOW);
@@ -429,11 +431,11 @@ void equi_main_loop() {
         /* hash and save compiled word */
         curtask->clt[curtask->cltp].nhash = crc16(&(curtask->literal_stack[0]), curtask->lsp);
         curtask->lsp = 0; /* clear the literal stack */
-        curtask->clt[curtask->cltp].loc = ram.cbp; /* stored the compiled code location from the most recent CBP value */
+        curtask->clt[curtask->cltp].loc = curtask->cbp; /* stored the compiled code location from the most recent CBP value */
         ++curtask->cltp; /* increase the word */
         if(curtask->cltp == CLT_ENTRIES_MAX)
           trapout(CLT_OVERFLOW);
-        ram.CM = 0; /* unset compilation mode flag */
+        curtask->CM = 0; /* unset compilation mode flag */
       }
       continue;
     }
@@ -448,8 +450,8 @@ void equi_main_loop() {
       pushLitVal();
     switch(instr) { /* then perform all main interpretation logic */
       case INS_CMSTART: /* compilation start */
-        ram.cbp = curtask->pc + 1U; /* save CBP */
-        ram.CM = 1U; /* raise CM flag */
+        curtask->cbp = curtask->pc + 1U; /* save CBP */
+        curtask->CM = 1U; /* raise CM flag */
         break;
       case CR:
       case LF:
@@ -630,7 +632,7 @@ void equi_main_loop() {
   /* close the persistent sandbox file if open */
   if(pfd) fclose(pfd);
   /* unset interpretation mode flag and exit */
-  ram.IM = 0;
+  curtask->IM = 0;
   curtask->pc = ram.ibp = 65535U;
   /* clear all stacks and CLT */
   curtask->msp = curtask->rsp = curtask->lsp = curtask->cltp = 0;
@@ -654,7 +656,7 @@ int main(int argc, char* argv[]) {
   ram.literal_stack_size = LIT_STACK_SIZE;
   ram.cmd_start = (uchar *)&ram.cmdbuf - (uchar *)&ram;
   ram.cmd_size = CMD_BUF_SIZE;
-  ram.II = ram.CM = ram.IM = ram.MM = 0; /* reset all flags */
+  ram.II = ram.MM = 0; /* reset all flags */
   ram.taskcount = 0;
   /* process command line params */
   if(argc > 1 && argv[1][0] == 'm') /* enter minification mode, don't run the programs */
@@ -706,7 +708,6 @@ int main(int argc, char* argv[]) {
           cputc(LF); /* echo LF */
         }
         ram.cmdbuf[++ram.ibp] = INS_QUIT; /* end program with INS_QUIT */
-        ram.IM = 1; /* set the mandatory interpretation mode flag */
         curtask = equi_load_task((ushort)ram.cmd_start, ram.ibp + 1); /* load the code as task 0 */
         equi_main_loop(); /* and run the interpreter loop */
         if(!smode) {