From bb8f16c858fe6a379b2af1f781e904ecbf5cd44b Mon Sep 17 00:00:00 2001
From: ketmar <ketmar@ketmar.no-ip.org>
Date: Thu, 5 Oct 2023 16:41:25 +0000
Subject: [PATCH] UrForth: fixed data stack trashing by condition compilation
 expression parser

FossilOrigin-Name: 95e6878794d592bad16e80d9b03af843ceaba9a6a42e4cba2741501aa05285b3
---
 src/urforth.c | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/src/urforth.c b/src/urforth.c
index c086634..cad1498 100644
--- a/src/urforth.c
+++ b/src/urforth.c
@@ -380,7 +380,7 @@ static void ufoErrorMsgV (const char *fmt, va_list ap) {
   vfprintf(stderr, fmt, ap);
   va_end(ap);
   fputc('\n', stderr);
-  fflush(stderr);
+  fflush(NULL);
 }
 
 
@@ -391,12 +391,15 @@ static void ufoErrorMsgV (const char *fmt, va_list ap) {
 //==========================================================================
 static void ufoStackTrace (void) {
   // dump data stack (top 16)
+  if (!ufoLastEmitWasCR) { printf("\n"); ufoLastEmitWasCR = 1; }
+  fflush(NULL);
+
   fprintf(stderr, "***UFO STACK DEPTH: %u\n", ufoSP);
   uint32_t xsp = ufoSP;
   if (xsp > 16) xsp = 16;
   for (uint32_t sp = 0; sp < xsp; ++sp) {
     fprintf(stderr, "  %2u: 0x%08x  %d\n", sp,
-           ufoDStack[xsp - sp - 1], (int32_t)ufoDStack[xsp - sp - 1]);
+            ufoDStack[xsp - sp - 1], (int32_t)ufoDStack[xsp - sp - 1]);
   }
   //if (ufoSP != 0) fputc('\n', stderr);
 
@@ -420,7 +423,7 @@ static void ufoStackTrace (void) {
     }
   }
 
-  fflush(stderr);
+  fflush(NULL);
 }
 
 
@@ -2239,6 +2242,7 @@ static void ufoParseNameToTempBuf (void) {
 static void ufoParseNameToTempBufEmptyOk (void) {
   UFCALL(PARSE_NAME);
   if (ufoPeek() == 0) {
+    ufo2Drop(); // drop zero-length string
     ufoTempCharBuf[0] = 0;
   } else {
     if (ufoPeek() > UFO_MAX_WORD_LENGTH) ufoFatal("word name too long");
@@ -5005,6 +5009,10 @@ UFWORD(DUMP_STACK) {
   }
 }
 
+// BACKTRACE
+UFWORD(UFO_BACKTRACE) {
+  ufoStackTrace();
+}
 
 // UFO-FATAL
 // ( addr count )
@@ -6251,6 +6259,7 @@ static void ufoInitCommon (void) {
 
   (void)ufoCreateVocSetOnlyDefs("DEBUG", NULL);
   UFWORDX("DUMP-STACK", DUMP_STACK);
+  UFWORDX("BACKTRACE", UFO_BACKTRACE);
   //ufoDefaultVocFlags |= UFW_FLAG_VOC_HIDDEN;
   UFWORDX("DECOMPILE", UFO_DECOMPILE_INTERNAL);
   UFWORDX("BP", UFO_BP);
-- 
2.11.4.GIT