[watcom,libc] Add weak symbol support for OpenWatcom in C Library

ghaerr · Aug 18, 2024 · 42a3edd · 42a3edd
1 parent 947ec1a
commit 42a3edd
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Showing 4 changed files with 24 additions and 10 deletions.
diff --git a/elkscmd/basic/host.c b/elkscmd/basic/host.c
@@ -54,11 +54,12 @@ float adjust(float f) {
 // for float testing compatibility, use same FP formatting routines on host for now
 // floats have approx 7 sig figs, 15 for double
 
-#if __ia16__
+#if __ia16__ || defined(__WATCOMC__)
 #include <sys/linksym.h>
-__STDIO_PRINT_FLOATS;       // link in libc printf float support
 
 char *host_floatToStr(float f, char *buf) {
+    __STDIO_PRINT_FLOATS;       // link in libc printf float support
+
 	sprintf(buf, "%.*g", MATH_PRECISION, (double)f);
     return buf;
 }

diff --git a/libc/include/sys/weaken.h b/libc/include/sys/weaken.h
@@ -3,13 +3,25 @@
 
 #ifdef __GNUC__
 /* return address of weak version of passed symbol */
-#define _weaken(sym) __extension__ ({                           \
+#define _weakaddr(sym) __extension__ ({                         \
+        extern __typeof__(sym) sym __attribute__((__weak__));   \
+        sym; })
+
+#define _weakfn(sym) __extension__ ({                           \
         extern __typeof__(sym) sym __attribute__((__weak__));   \
         sym; })
 #endif
 
 #ifdef __WATCOMC__
-#define _weaken(sym)    (sym)   /* FIXME weak symbols not yet implemented */
+
+#if defined(__COMPACT__) || defined(__LARGE__)
+/* FIXME: this can fail if weak symbol happens to fall at address zero of segment! */
+#define _weakaddr(sym)  (((unsigned long)sym) & 0xFFFF)
+#else
+#define _weakaddr(sym)  (sym)
+#endif
+
+#define _weakfn(sym)    (sym)
 #endif
 
 #endif
diff --git a/libc/stdio/Makefile b/libc/stdio/Makefile
@@ -55,6 +55,9 @@ all: $(LIB)
 
 $(LIB): $(LIBOBJS)
 	$(RM) $@
+ifeq "$(COMPILER)" "watcom"
+	fixomf -w dtostr_,ptostr_ vfprintf.obj
+endif
 	$(AR) $(ARFLAGS_SUB) $@ $(LIBOBJS)
 
 clean:

diff --git a/libc/stdio/vfprintf.c b/libc/stdio/vfprintf.c
@@ -218,16 +218,14 @@ vfprintf(FILE *op, const char *fmt, va_list ap)
 	 case 'k':		/* Pticks */
 	  usproc:
 	    l = lval? va_arg(ap, unsigned long) : (unsigned long)va_arg(ap, unsigned int);
-#ifndef __WATCOMC__
 	    if (*fmt == 'k') {
-		if (_weaken(ptostr)) {
-		    (_weaken(ptostr))(l, ptmp);
+		if (_weakaddr(ptostr)) {
+		    (_weakfn(ptostr))(l, ptmp);
 		    preci = -1;
 		    goto printit;
 		}
 		/* if precision timing not linked in, display as unsigned */
 	    }
-#endif
 	    ptmp = ultostr(l, radix);
 	    if( hash && radix == 8 ) { width = strlen(ptmp)+1; pad='0'; }
 	    goto printit;
@@ -258,9 +256,9 @@ vfprintf(FILE *op, const char *fmt, va_list ap)
 	 case 'g':
 	 case 'E':
 	 case 'G':
-	    if (_weaken(dtostr))
+	    if (_weakaddr(dtostr))
 	    {
-	       (_weaken(dtostr))(va_arg(ap, double), *fmt, preci, ptmp);
+	       (_weakfn(dtostr))(va_arg(ap, double), *fmt, preci, ptmp);
 	       preci = -1;
 	       goto printit;
 	    }