From c65a2f634b8ca75cceeb79a9afbc381a7ae0362f Mon Sep 17 00:00:00 2001
From: "H. Peter Anvin" <hpa@zytor.com>
Date: Mon, 22 Oct 2007 17:34:10 -0700
Subject: [PATCH] Support binary and octal floating-point

For consistency, support binary and octal floating-point, and accept
a "0d" or "0t" prefix for decimal floating-point.  However, we do not
accept a binary exponent (p) for a decimal mantissa, or vice versa.
---
 float.c        | 78 ++++++++++++++++++++++++++++++++++++++++------------------
 stdscan.c      |  2 +-
 test/radix.asm | 19 +++++++++++++-
 3 files changed, 73 insertions(+), 26 deletions(-)

diff --git a/float.c b/float.c
index a2df323d..7e99f96c 100644
--- a/float.c
+++ b/float.c
@@ -424,29 +424,33 @@ static bool ieee_round(int sign, uint16_t * mant, int32_t i)
     return false;
 }
 
-static int hexval(char c)
+/* Returns a value >= 16 if not a valid hex digit */
+static unsigned int hexval(char c)
 {
-    if (c >= '0' && c <= '9')
-        return c - '0';
-    else if (c >= 'a' && c <= 'f')
-        return c - 'a' + 10;
+    unsigned int v = (unsigned char) c;
+
+    if (v >= '0' && v <= '9')
+        return v - '0';
     else
-        return c - 'A' + 10;
+        return (v|0x20) - 'a' + 10;
 }
 
-static bool ieee_flconvert_hex(const char *string, uint16_t * mant,
-                               int32_t * exponent)
+/* Handle floating-point numbers with radix 2^bits and binary exponent */
+static bool ieee_flconvert_bin(const char *string, int bits,
+			       uint16_t * mant, int32_t * exponent)
 {
     static const int log2tbl[16] =
         { -1, 0, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3 };
     uint16_t mult[MANT_WORDS + 1], *mp;
     int ms;
     int32_t twopwr;
-    int seendot, seendigit;
+    bool seendot, seendigit;
     unsigned char c;
+    int radix = 1 << bits;
+    unsigned int v;
 
     twopwr = 0;
-    seendot = seendigit = 0;
+    seendot = seendigit = false;
     ms = 0;
     mp = NULL;
 
@@ -461,17 +465,15 @@ static bool ieee_flconvert_hex(const char *string, uint16_t * mant,
                       "too many periods in floating-point constant");
                 return false;
             }
-        } else if (isxdigit(c)) {
-            int v = hexval(c);
-
+        } else if ((v = hexval(c)) < (unsigned int)radix) {
             if (!seendigit && v) {
                 int l = log2tbl[v];
 
                 seendigit = 1;
                 mp = mult;
-                ms = 15 - l;
+                ms = 15-l;
 
-                twopwr = seendot ? twopwr - 4 + l : l - 3;
+                twopwr = seendot ? twopwr-bits+l : l+1-bits;
             }
 
             if (seendigit) {
@@ -483,13 +485,13 @@ static bool ieee_flconvert_hex(const char *string, uint16_t * mant,
                     ms += 16;
                 }
                 *mp |= v << ms;
-                ms -= 4;
+                ms -= bits;
 
                 if (!seendot)
-                    twopwr += 4;
+                    twopwr += bits;
             } else {
                 if (seendot)
-                    twopwr -= 4;
+                    twopwr -= bits;
             }
         } else if (c == 'p' || c == 'P') {
 	    int32_t e;
@@ -656,13 +658,41 @@ static int to_float(const char *str, int sign, uint8_t * result,
 	    break;
         }
     } else {
-        if (str[0] == '0' &&
-	    (str[1] == 'x' || str[1] == 'X' || str[1] == 'h' || str[1] == 'H'))
-            ok = ieee_flconvert_hex(str + 2, mant, &exponent);
-	else if (str[0] == '$')
-	    ok = ieee_flconvert_hex(str + 1, mant, &exponent);
-        else
+        if (str[0] == '0') {
+	    switch (str[1]) {
+	    case 'x': case 'X':
+	    case 'h': case 'H':
+		ok = ieee_flconvert_bin(str+2, 4, mant, &exponent);
+		break;
+	    case 'o': case 'O':
+	    case 'q': case 'Q':
+		ok = ieee_flconvert_bin(str+2, 3, mant, &exponent);
+		break;
+	    case 'b': case 'B':
+	    case 'y': case 'Y':
+		ok = ieee_flconvert_bin(str+2, 1, mant, &exponent);
+		break;
+	    case 'd': case 'D':
+	    case 't': case 'T':
+		ok = ieee_flconvert(str+2, mant, &exponent);
+		break;
+	    case '0': case '1': case '2': case '3': case '4':
+	    case '5': case '6': case '7': case '8': case '9':
+	    case '\0':
+		/* Leading zero was just a zero */
+		ok = ieee_flconvert(str, mant, &exponent);
+		break;
+	    default:
+		error(ERR_NONFATAL,
+		      "floating-point constant: invalid radix `%c'", str[1]);
+		ok = false;
+		break;
+	    }
+	} else if (str[0] == '$') {
+	    ok = ieee_flconvert_bin(str+1, 4, mant, &exponent);
+	} else {
             ok = ieee_flconvert(str, mant, &exponent);
+	}
 
 	if (!ok) {
 	    type = FL_QNAN;
diff --git a/stdscan.c b/stdscan.c
index dda4e0a3..8295054a 100644
--- a/stdscan.c
+++ b/stdscan.c
@@ -141,7 +141,7 @@ int stdscan(void *private_data, struct tokenval *tv)
 		}
 	    } else if (c == 'H' || c == 'h' || c == 'X' || c == 'x') {
 		is_hex = true;
-	    } else if (is_hex && (c == 'P' || c == 'p')) {
+	    } else if (c == 'P' || c == 'p') {
 		is_float = true;
 		if (*stdscan_bufptr == '+' || *stdscan_bufptr == '-')
 		    stdscan_bufptr++;
diff --git a/test/radix.asm b/test/radix.asm
index 35dbceef..c08b5500 100644
--- a/test/radix.asm
+++ b/test/radix.asm
@@ -1,3 +1,5 @@
+	;;  Integer constants...
+
 	dd 1010_0101		; Decimal
 	dd 01010_0101		; Decimal (*not* octal!)
 	dd 0d1010_0101		; Decimal
@@ -20,4 +22,19 @@
 	dd 1010_0101h		; Hex
 	dd 1010_0101x		; Hex
 	dd $1010_0101		; Hex
-	
\ No newline at end of file
+
+	;; Floating-point constants
+	;; All of these should output B4A21147
+	dd 3.7282705e+4		; Decimal
+	dd 00003.7282705e+4 	; Decimal
+	dd 0d3.7282705e+4	; Decimal
+	dd 0t3.7282705e+4	; Decimal
+
+	dd 0x1.23456789p+15	; Hex
+	dd 0h1.23456789p+15	; Hex
+	
+	dd 0o1.10642547422p+15	; Octal
+	dd 0q1.10642547422p+15	; Octal
+
+	dd 0b1.0010_0011_0100_0101_0110_0111_1000_1001p+15 ; Binary
+	dd 0y1.0010_0011_0100_0101_0110_0111_1000_1001p+15 ; Binary
-- 
2.11.4.GIT