1 files changed, 41 insertions, 0 deletions
diff --git a/libc/ctype/toascii.c b/libc/ctype/toascii.c
new file mode 100644
index 0000000..4506f35
--- /dev/null
+++ b/libc/ctype/toascii.c
@@ -0,0 +1,41 @@
+/*
+FUNCTION
+	<<toascii>>---force integers to ASCII range
+
+INDEX
+	toascii
+
+ANSI_SYNOPSIS
+	#include <ctype.h>
+	int toascii(int <[c]>);
+
+TRAD_SYNOPSIS
+	#include <ctype.h>
+	int toascii(<[c]>);
+	int (<[c]>);
+
+DESCRIPTION
+<<toascii>> is a macro which coerces integers to the ASCII range (0--127) by zeroing any higher-order bits.
+
+You can use a compiled subroutine instead of the macro definition by
+undefining this macro using `<<#undef toascii>>'.
+
+RETURNS
+<<toascii>> returns integers between 0 and 127.
+
+PORTABILITY
+<<toascii>> is not ANSI C.
+
+No supporting OS subroutines are required.
+*/
+
+#include <_ansi.h>
+#include <ctype.h>
+#undef toascii
+
+int
+_DEFUN(toascii,(c),int c)
+{
+  return (c)&0177;
+}
+