Support generating NaNs and infinities

Support generating NaNs and infinities as part of floating-point
constants.

diff --git a/float.c b/float.c
index b87db84..d22aa19 100644 (file)
--- a/float.c
+++ b/float.c
@@ -303,6 +303,12 @@ static int ieee_round(uint16_t *mant, int i)
 
 #define put(a,b) ( (*(a)=(b)), ((a)[1]=(b)>>8) )
 
+/* Set a bit, using *bigendian* bit numbering (0 = MSB) */
+static void set_bit(uint16_t *mant, int bit)
+{
+    mant[bit >> 4] |= 1 << (~bit & 15);
+}
+
 /* Produce standard IEEE formats, with implicit "1" bit; this makes
    the following assumptions:
 
@@ -333,59 +339,84 @@ static int to_float(char *str, int32_t sign, uint8_t *result,
 
     sign = (sign < 0 ? 0x8000L : 0L);
 
-    ieee_flconvert(str, mant, &exponent, error);
-    if (mant[0] & 0x8000) {
-        /*
-         * Non-zero.
-         */
-        exponent--;
-        if (exponent >= 2-expmax && exponent <= expmax) {
-            /*
-             * Normalised.
-             */
-            exponent += expmax;
-            ieee_shr(mant, fmt->exponent);
-            ieee_round(mant, fmt->words);
-           /* did we scale up by one? */
-            if (mant[0] & (implicit_one << 1)) {
-                ieee_shr(mant, 1);
-               exponent++;
-           }
+    if (str[0] == '_') {
+       /* NaN or Infinity */
+       int32_t expmask = (1 << fmt->exponent)-1;
 
-            mant[0] &= (implicit_one-1);     /* remove leading one */
-           mant[0] |= exponent << (15 - fmt->exponent);
-        } else if (exponent < 2-expmax && exponent >= 2-expmax-fmt->mantissa) {
-            /*
-             * Denormal.
-             */
-            int shift = -(exponent + expmax-2-fmt->exponent);
-            int sh = shift % 16, wds = shift / 16;
-            ieee_shr(mant, sh);
-            if (ieee_round(mant, fmt->words - wds)
-                || (sh > 0 && (mant[0] & (0x8000 >> (sh - 1))))) {
-                ieee_shr(mant, 1);
-                if (sh == 0)
-                    mant[0] |= 0x8000;
-                exponent++;
-            }
+       memset(mant, 0, sizeof mant);
+       mant[0] = expmask << (15-fmt->exponent); /* Exponent: all bits one */
 
-           if (wds) {
-               for (i = fmt->words-1; i >= wds; i--)
-                   mant[i] = mant[i-wds];
-               for (; i >= 0; i--)
-                   mant[i] = 0;
-           }
-        } else {
-            if (exponent > 0) {
-                error(ERR_NONFATAL, "overflow in floating-point constant");
-                return 0;
+       switch (str[2]) {
+       case 'n':               /* __nan__ */
+       case 'N':
+       case 'q':               /* __qnan__ */
+       case 'Q':
+           set_bit(mant, fmt->exponent+1); /* Highest bit in mantissa */
+           break;
+       case 's':               /* __snan__ */
+       case 'S':
+           set_bit(mant, fmt->exponent+fmt->mantissa); /* Last bit */
+           break;
+       case 'i':               /* __infinity__ */
+       case 'I':
+           break;
+       }
+    } else {
+       ieee_flconvert(str, mant, &exponent, error);
+       if (mant[0] & 0x8000) {
+           /*
+            * Non-zero.
+            */
+           exponent--;
+           if (exponent >= 2-expmax && exponent <= expmax) {
+               /*
+                * Normalised.
+                */
+               exponent += expmax;
+               ieee_shr(mant, fmt->exponent);
+               ieee_round(mant, fmt->words);
+               /* did we scale up by one? */
+               if (mant[0] & (implicit_one << 1)) {
+                   ieee_shr(mant, 1);
+                   exponent++;
+               }
+               
+               mant[0] &= (implicit_one-1);     /* remove leading one */
+               mant[0] |= exponent << (15 - fmt->exponent);
+           } else if (exponent < 2-expmax &&
+                      exponent >= 2-expmax-fmt->mantissa) {
+               /*
+                * Denormal.
+                */
+               int shift = -(exponent + expmax-2-fmt->exponent);
+               int sh = shift % 16, wds = shift / 16;
+               ieee_shr(mant, sh);
+               if (ieee_round(mant, fmt->words - wds)
+                   || (sh > 0 && (mant[0] & (0x8000 >> (sh - 1))))) {
+                   ieee_shr(mant, 1);
+                   if (sh == 0)
+                       mant[0] |= 0x8000;
+                   exponent++;
+               }
+               
+               if (wds) {
+                   for (i = fmt->words-1; i >= wds; i--)
+                       mant[i] = mant[i-wds];
+                   for (; i >= 0; i--)
+                       mant[i] = 0;
+               }
            } else {
-               memset(mant, 0, 2*fmt->words);
+               if (exponent > 0) {
+                   error(ERR_NONFATAL, "overflow in floating-point constant");
+                   return 0;
+               } else {
+                   memset(mant, 0, 2*fmt->words);
+               }
            }
-        }
-    } else {
-       /* Zero */
-        memset(mant, 0, 2*fmt->words);
+       } else {
+           /* Zero */
+           memset(mant, 0, 2*fmt->words);
+       }
     }
 
     mant[0] |= sign;
@@ -409,6 +440,31 @@ static int to_ldoub(char *str, int32_t sign, uint8_t *result,
 
     sign = (sign < 0 ? 0x8000L : 0L);
 
+    if (str[0] == '_') {
+       uint16_t is_snan = 0, is_qnan = 0x8000;
+       switch (str[2]) {
+       case 'n':
+       case 'N':
+       case 'q':
+       case 'Q':
+           is_qnan = 0xc000;
+           break;
+       case 's':
+       case 'S':
+           is_snan = 1;
+           break;
+       case 'i':
+       case 'I':
+           break;
+       }
+       put(result + 0, is_snan);
+       put(result + 2, 0);
+       put(result + 4, 0);
+       put(result + 6, is_qnan);
+       put(result + 8, 0x7fff|sign);
+       return 1;
+    }
+
     ieee_flconvert(str, mant, &exponent, error);
     if (mant[0] & 0x8000) {
         /*
@@ -422,11 +478,11 @@ static int to_ldoub(char *str, int32_t sign, uint8_t *result,
             exponent += 16383;
             if (ieee_round(mant, 4))    /* did we scale up by one? */
                 ieee_shr(mant, 1), mant[0] |= 0x8000, exponent++;
-            put(result + 8, exponent | sign);
-            put(result + 6, mant[0]);
-            put(result + 4, mant[1]);
-            put(result + 2, mant[2]);
             put(result + 0, mant[3]);
+            put(result + 2, mant[2]);
+            put(result + 4, mant[1]);
+            put(result + 6, mant[0]);
+            put(result + 8, exponent | sign);
         } else if (exponent < -16383 && exponent >= -16446) {
             /*
              * Denormal.
@@ -441,23 +497,29 @@ static int to_ldoub(char *str, int32_t sign, uint8_t *result,
                     mant[0] |= 0x8000;
                 exponent++;
             }
-            put(result + 8, sign);
-            put(result + 6, (wds == 0 ? mant[0] : 0));
-            put(result + 4, (wds <= 1 ? mant[1 - wds] : 0));
-            put(result + 2, (wds <= 2 ? mant[2 - wds] : 0));
             put(result + 0, (wds <= 3 ? mant[3 - wds] : 0));
+            put(result + 2, (wds <= 2 ? mant[2 - wds] : 0));
+            put(result + 4, (wds <= 1 ? mant[1 - wds] : 0));
+            put(result + 6, (wds == 0 ? mant[0] : 0));
+            put(result + 8, sign);
         } else {
             if (exponent > 0) {
                 error(ERR_NONFATAL, "overflow in floating-point constant");
                 return 0;
-            } else
-                memset(result, 0, 10);
+            } else {
+               goto zero;
+           }
         }
     } else {
         /*
          * Zero.
          */
-        memset(result, 0, 10);
+    zero:
+       put(result + 0, 0);
+       put(result + 2, 0);
+       put(result + 4, 0);
+       put(result + 6, 0);
+       put(result + 8, sign);
     }
     return 1;
 }

diff --git a/insns.h b/insns.h
index b025c7a..314737a 100644 (file)
--- a/insns.h
+++ b/insns.h
@@ -12,10 +12,10 @@
 #include "nasm.h"
 
 /* max length of any instruction, register name etc. */
-#if MAX_INSLEN > 9              /* MAX_INSLEN defined in insnsi.h */
+#if MAX_INSLEN > 12              /* MAX_INSLEN defined in insnsi.h */
 #define MAX_KEYWORD MAX_INSLEN
 #else
-#define MAX_KEYWORD 9
+#define MAX_KEYWORD 12
 #endif
 
 struct itemplate {

diff --git a/test/float.asm b/test/float.asm
index 30d1f06..bcb2ec2 100644 (file)
--- a/test/float.asm
+++ b/test/float.asm
@@ -21,6 +21,12 @@
        dw 1.83203125e-6                ; Denormal!
        dw +1.83203125e-6               ; Denormal!
        dw -1.83203125e-6               ; Denormal!
+       dw __Infinity__
+       dw +__Infinity__
+       dw -__Infinity__
+       dw __NaN__
+       dw __QNaN__
+       dw __SNaN__
 
 ; 32-bit
        dd 1.0
@@ -41,6 +47,12 @@
        dd 1.83203125e-40               ; Denormal!
        dd +1.83203125e-40              ; Denormal!
        dd -1.83203125e-40              ; Denormal!
+       dd __Infinity__
+       dd +__Infinity__
+       dd -__Infinity__
+       dd __NaN__
+       dd __QNaN__
+       dd __SNaN__
 
 ; 64-bit
        dq 1.0
@@ -61,6 +73,12 @@
        dq 1.83203125e-320              ; Denormal!
        dq +1.83203125e-320             ; Denormal!
        dq -1.83203125e-320             ; Denormal!
+       dq __Infinity__
+       dq +__Infinity__
+       dq -__Infinity__
+       dq __NaN__
+       dq __QNaN__
+       dq __SNaN__
 
 ; 80-bit
        dt 1.0
@@ -81,6 +99,12 @@
        dt 1.83203125e-4940             ; Denormal!
        dt +1.83203125e-4940            ; Denormal!
        dt -1.83203125e-4940            ; Denormal!
+       dt __Infinity__
+       dt +__Infinity__
+       dt -__Infinity__
+       dt __NaN__
+       dt __QNaN__
+       dt __SNaN__
 
 ; 128-bit
        do 1.0
@@ -101,3 +125,9 @@
        do 1.83203125e-4940             ; Denormal!
        do +1.83203125e-4940            ; Denormal!
        do -1.83203125e-4940            ; Denormal!
+       do __Infinity__
+       do +__Infinity__
+       do -__Infinity__
+       do __NaN__
+       do __QNaN__
+       do __SNaN__

diff --git a/tokens.dat b/tokens.dat
index c84b8fb..e7c1cb2 100644 (file)
--- a/tokens.dat
+++ b/tokens.dat
@@ -32,6 +32,12 @@ to
 tword
 word
 
+% TOKEN_FLOAT, 0, 0
+__infinity__
+__nan__
+__qnan__
+__snan__
+
 % TOKEN_*, 0, 0
 seg
 wrt