Basic VM and other minor improvements.

Not complete, probably not fully debugged or optimized.

lib/sysutil/stacktrace.c

@@ -0,0 +1,63 @@
+/*
+stacktrace.c
+
+Created:	Jan 19, 1993 by Philip Homburg
+
+Copyright 1995 Philip Homburg
+*/
+
+typedef unsigned int reg_t;
+
+#define FUNC_STACKTRACE(statement) 				\
+{								\
+	reg_t bp, pc, hbp;					\
+	extern reg_t get_bp(void);				\
+								\
+	bp= get_bp();						\
+	while(bp)						\
+	{							\
+		pc= ((reg_t *)bp)[1];				\
+		hbp= ((reg_t *)bp)[0];				\
+		statement;					\
+		if (hbp != 0 && hbp <= bp)			\
+		{						\
+			pc = -1;				\
+			statement;				\
+			break;					\
+		}						\
+		bp= hbp;					\
+	}							\
+}
+
+void util_nstrcat(char *str, unsigned long number)
+{
+	int n = 10, lead = 1;
+	char nbuf[12], *p;
+	p = nbuf;
+	*p++ = '0';
+	*p++ = 'x';
+	for(n = 0; n < 8; n++) {
+		int i;
+		i = (number >> ((7-n)*4)) & 0xF;
+		if(!lead || i) {
+			*p++ = i < 10 ? '0' + i : 'a' + i - 10;
+			lead = 0;
+		}
+	}
+	if(lead) *p++ = '0';
+	*p++ = ' ';
+	*p++ = '\0';
+	strcat(str, nbuf);
+}
+
+void util_stacktrace(void)
+{
+	FUNC_STACKTRACE(printf("0x%lx ", (unsigned long) pc));
+	printf("\n");
+}
+
+void util_stacktrace_strcat(char *str)
+{
+	FUNC_STACKTRACE(util_nstrcat(str, pc));
+}
+