From e2250e5cb71c9a06bf75d59e9c0369efd65b1206 Mon Sep 17 00:00:00 2001
From: "B. Watson" <urchlay@slackware.uk>
Date: Sun, 16 Jun 2024 17:33:22 -0400
Subject: cxrefbas: added.

---
 bcdfp.c | 56 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 56 insertions(+)
 create mode 100644 bcdfp.c

(limited to 'bcdfp.c')

diff --git a/bcdfp.c b/bcdfp.c
new file mode 100644
index 0000000..76157c1
--- /dev/null
+++ b/bcdfp.c
@@ -0,0 +1,56 @@
+#include <string.h>
+#include "bcdfp.h"
+
+extern void die(const char *msg);
+
+unsigned char bcd2int(unsigned char bcd) {
+	return (bcd >> 4) * 10 + (bcd & 0x0f);
+}
+
+unsigned char int2bcd(unsigned char i) {
+	return ((i / 10) << 4) | (i % 10);
+}
+
+unsigned short fp2int(const unsigned char *fp) {
+	unsigned short result = 0;
+
+	/* examine the exponent/sign byte */
+	if(fp[0] == 0) return 0; /* special case */
+	if(fp[0] & 0x80) die("negative numbers not supported");
+
+	switch(fp[0]) {
+		case 0x40:
+			result = bcd2int(fp[1]); break;
+		case 0x41:
+			result = bcd2int(fp[1]) * 100 + bcd2int(fp[2]); break;
+		case 0x42:
+			result = bcd2int(fp[1]) * 10000 + bcd2int(fp[2]) * 100 + bcd2int(fp[3]); break;
+		default:
+			die("number out of range"); break;
+	}
+
+	return result;
+}
+
+void int2fp(unsigned short num, unsigned char *fp) {
+	memset(fp, 0, 6);
+
+	if(num == 0) return;
+
+	if(num >= 10000) {
+		fp[0] = 0x42;
+		fp[3] = int2bcd(num % 100);
+		num /= 100;
+		fp[2] = int2bcd(num % 100);
+		num /= 100;
+		fp[1] = int2bcd(num);
+	} else if(num >= 100) {
+		fp[0] = 0x41;
+		fp[2] = int2bcd(num % 100);
+		num /= 100;
+		fp[1] = int2bcd(num);
+	} else {
+		fp[0] = 0x40;
+		fp[1] = int2bcd(num);
+	}
+}
-- 
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