From 31166c8e7f9eeccf19ed1ee412efe94b42f3de72 Mon Sep 17 00:00:00 2001
From: Luxferre <lux@ferre>
Date: Tue, 9 Aug 2022 07:47:50 +0300
Subject: [PATCH] Temporarily commented out strip

---
 Makefile |  2 +-
 equi.c   | 72 +++++++++++++++++++++++++++++++++++++++++---------------
 2 files changed, 54 insertions(+), 20 deletions(-)

diff --git a/Makefile b/Makefile
index 6c314af..fffc73d 100644
--- a/Makefile
+++ b/Makefile
@@ -7,7 +7,7 @@ DFLAGS=
 
 desktopcc:
 	cc -std=c89 -Os -o $(PROJNAME) $(CFILES) $(DFLAGS)
-	strip $(PROJNAME)
+	#strip $(PROJNAME)
 
 tcc:
 	tcc -std=c89 -o $(PROJNAME) $(CFILES) $(DFLAGS)
diff --git a/equi.c b/equi.c
index ed94fdc..db4c308 100644
--- a/equi.c
+++ b/equi.c
@@ -80,8 +80,8 @@
  */
 
 struct CLTEntry {
-  uchar name[CLT_ENTRY_LEN]; /* compiled word name */
-  ushort loc;    /* compiled word location */
+  ushort nhash; /* compiled word name hash */
+  ushort loc;   /* compiled word location */
 };
 
 struct EquiRAM { 
@@ -121,6 +121,7 @@ enum EquiErrors {
   CLT_OVERFLOW,
   CMD_OVERFLOW,
   INVALID_INSTRUCTION,
+  INVALID_WORD,
   PORT_IO_ERROR
 };
 
@@ -147,6 +148,9 @@ void trapout(errcode) {
       case INVALID_INSTRUCTION:
         cerr("Invalid instruction");
         break;
+      case INVALID_WORD:
+        cerr("Word not found in CLT");
+        break;
       case PORT_IO_ERROR:
         cerr("Port I/O error");
         break;
@@ -216,16 +220,20 @@ void pushRet(ushort val) {
 
 /* pop a value from the main stack */
 ushort popMain() {
-  if(ram.msp == 0)
+  if(ram.msp == 0) {
     trapout(STACK_UNDERFLOW);
+    return 0;
+  }
   else
     return ram.main_stack[--ram.msp];
 }
 
 /* pop a value from the return stack */
 ushort popRet() {
-  if(ram.rsp == 0)
+  if(ram.rsp == 0) {
     trapout(STACK_UNDERFLOW);
+    return 0;
+  }
   else
     return ram.return_stack[--ram.rsp];
 }
@@ -239,8 +247,10 @@ void pushLit(uchar c) {
 
 /* pop a character from the literal stack */
 uchar popLit() {
-  if(ram.lsp == 0)
+  if(ram.lsp == 0) {
     trapout(STACK_UNDERFLOW);
+    return 0;
+  }
   else
     return ram.literal_stack[--ram.lsp];
 }
@@ -253,7 +263,7 @@ void clearLit() {
 /* shape 2-byte vlaue on the main stack from the 4 values of the literal stack */
 void pushLitVal(strict) {
   uchar p1, p2, p3, p4;
-  if(ram.lsp < 4) { /* if we don't strictly expect 4 bytes, do nothing */
+  if(ram.lsp < 4U) { /* if we don't strictly expect 4 bytes, do nothing */
     if(strict) trapout(STACK_UNDERFLOW);
     else {
       ram.lsp = 0; /* clear the literal stack */
@@ -265,19 +275,33 @@ void pushLitVal(strict) {
     p3 = popLit();
     p2 = popLit();
     p1 = popLit();
-    pushMain((p1<<12) | (p2<<8) | (p3<<4) | p4);
+    pushMain((p1<<12U) | (p2<<8U) | (p3<<4U) | p4);
     ram.lsp = 0; /* clear the literal stack */
   }
 }
 
+/* CCITT CRC16 helper */
+
+ushort crc16(const uchar* data_p, uchar length) {
+  uchar x;
+  ushort crc = 0xFFFFu;
+  while(length--) {
+    x = crc>>8U ^ *data_p++;
+    x ^= x>>4U;
+    crc = (crc << 8U) ^ ((ushort)(x << 12U)) ^ ((ushort)(x << 5U)) ^ ((ushort)x);
+  }
+  return crc;
+}
+
 /* Main interpreter loop */
 
 void equi_main_loop() {
   uchar instr, i;
+  ushort lhash, pbuf;
   /* reset all stacks before running and reinit CLT */
   ram.msp = ram.rsp = ram.lsp = ram.cltp = 0;
   /* reset pc */
-  ram.pc = 65535;
+  ram.pc = 65535U;
   while(1) { /* iterate over the instructions in the command buffer */
     instr = ram.cmdbuf[++ram.pc];
     /* first, check for II mode */
@@ -289,17 +313,16 @@ void equi_main_loop() {
     /* then, check for compilation mode */
     if(ram.CM) {
       if(instr == INS_CMEND) { /* trigger word compilation logic as per the spec */
+        if(ram.lsp < CLT_ENTRY_LEN)
+          trapout(STACK_UNDERFLOW);
         ram.cmdbuf[ram.pc] = INS_RET; /* in-place patch this instruction to R */
-        /* compiled words are saved vice versa to save code size */
-        for(i=0;i<CLT_ENTRY_LEN;++i)
-          ram.clt[ram.cltp].name[i] = popLit();
+        /* hash and save compiled word */
+        ram.clt[ram.cltp].nhash = crc16(&ram.literal_stack[ram.lsp-CLT_ENTRY_LEN], CLT_ENTRY_LEN);
         ram.lsp = 0; /* clear the literal stack */
         ram.clt[ram.cltp].loc = ram.cbp; /* stored the compiled code location from the most recent CBP value */
         ++ram.cltp; /* increase the word */
-        if(ram.cltp == CLT_ENTRIES_MAX) {
+        if(ram.cltp == CLT_ENTRIES_MAX)
           trapout(CLT_OVERFLOW);
-          break;
-        }
         ram.CM = 0; /* unset compilation mode flag */
       }
       continue;
@@ -318,17 +341,28 @@ void equi_main_loop() {
         ram.II = 1; /* raise II flag */
         break;
       case INS_CMSTART: /* compilation start */
-        ram.cbp = ram.pc + 1; /* save CBP */
-        ram.CM = 1; /* raise CM flag */
+        ram.cbp = ram.pc + 1U; /* save CBP */
+        ram.CM = 1U; /* raise CM flag */
         break;
       case INS_QUIT: /* gracefully quit the interpretation mode */
         goto brx;
       case INS_LITINT: /* literal stack -> main stack as short */
-        pushLitVal(1);
+        pushLitVal(1U);
         break;
       case INS_LITSTR:
         break;
-      case INS_LITCALL:
+      case INS_LITCALL: /* call the saved word from the literal */
+        if(ram.lsp < CLT_ENTRY_LEN)
+          trapout(STACK_UNDERFLOW);
+        lhash = crc16(&ram.literal_stack[ram.lsp-CLT_ENTRY_LEN], CLT_ENTRY_LEN);
+        for(pbuf=0;pbuf<CLT_ENTRIES_MAX;++pbuf)
+          if(ram.clt[pbuf].nhash == lhash) {
+            ram.pc = ram.clt[pbuf].loc;
+            break;
+          }
+        if(pbuf >= CLT_ENTRIES_MAX)
+          trapout(INVALID_WORD);
+        ram.lsp = 0; /* clear the literal stack */
         break;
       case INS_RET:
         ram.pc = popRet();
@@ -421,7 +455,7 @@ int main(int argc, char* argv[]) {
   ram.cmd_size = CMD_BUF_SIZE;
   ram.II = ram.CM = ram.IM = 0; /* reset all flags */
   /* Start both execution and input buffering from the start of command buffer (-1 because we use prefix increment) */
-  ram.pc = ram.ibp = ram.cmd_start-1;
+  ram.pc = ram.ibp = 65535U;
 
   printf("Welcome to Equi v" EQUI_VER " by Luxferre, 2022\n\nCLT: 0x%X (%d bytes)\nGPD: 0x%X (%d bytes)\nCommand buffer: 0x%X (%d bytes)\nEqui ready\n\n",
       (uchar *)&ram.clt - (uchar *)&ram.main_stack,