* device/include/float.h: added __INFINITY

[fw/sdcc] / device / lib / _fsdiv.c

diff --git a/device/lib/_fsdiv.c b/device/lib/_fsdiv.c
index 1768ec46a9b21c9ee3d2e5c0b29d6f833e2f3e2a..7bf1c48f010293a75054c269f0f63a06bcb0ac53 100644 (file)
--- a/device/lib/_fsdiv.c
+++ b/device/lib/_fsdiv.c
@@ -23,10 +23,10 @@
 
 #ifdef FLOAT_ASM_MCS51
 
-// float __fsdiv (float a, float b) reentrant
-static void dummy(void) _naked
+// float __fsdiv (float a, float b) __reentrant
+static void dummy(void) __naked
 {
-       _asm
+       __asm
        .globl  ___fsdiv
 ___fsdiv:
        // extract the two inputs, placing them into:
@@ -42,20 +42,52 @@ ___fsdiv:
        cpl     sign_a
 00001$:
 
-       // if divisor is zero, return infinity
-       cjne    r7, #0, 00002$
-       ljmp    fs_return_inf
+       // if divisor is zero, ...
+       cjne    r7, #0, 00003$
+       // if dividend is also zero, return NaN
+       cjne    r4, #0, 00002$
+       ljmp    fs_return_nan
 00002$:
+       // but dividend is non-zero, return infinity
+       ljmp    fs_return_inf
+00003$:
        // if dividend is zero, return zero
-       cjne    r4, #0, 00003$
+       cjne    r4, #0, 00004$
        ljmp    fs_return_zero
-00003$:
+00004$:
+       // if divisor is infinity, ...
+       mov     a, exp_b
+       cjne    a, #0xFF, 00006$
+       // and dividend is also infinity, return NaN
+       mov     a, exp_a
+       cjne    a, #0xFF, 00005$
+       ljmp    fs_return_nan
+00005$:
+       // but dividend is not infinity, return zero
+       ljmp    fs_return_zero
+00006$:
+       // if dividend is infinity, return infinity
+       mov     a, exp_a
+       cjne    a, #0xFF, 00007$
+       ljmp    fs_return_inf
+00007$:
 
        // subtract exponents
        clr     c
-       mov     a, exp_a
        subb    a, exp_b
+       // if no carry then no underflow
+       jnc     00008$
        add     a, #127
+       jc      00009$
+       ljmp    fs_return_zero
+
+00008$:
+       add     a, #128
+       dec     a
+       jnc     00009$
+       ljmp    fs_return_inf
+
+00009$:
        mov     exp_a, a
 
        // need extra bits on a's mantissa
@@ -67,7 +99,7 @@ ___fsdiv:
        subb    a, r3
        mov     a, r7
        subb    a, r4
-       jc      00005$
+       jc      00010$
        dec     exp_a
        clr     c
        mov     a, r2
@@ -82,15 +114,15 @@ ___fsdiv:
        clr     a
        rlc     a
        mov     r4, a
-       sjmp    00006$
-00005$:
+       sjmp    00011$
+00010$:
 #endif
        clr     a
        xch     a, r4
        xch     a, r3
        xch     a, r2
        mov     r1, a
-00006$:
+00011$:
 
        // begin long division
        push    exp_a
@@ -99,7 +131,7 @@ ___fsdiv:
 #else
        mov     b, #24
 #endif
-00010$:
+00012$:
        // compare
        clr     c
        mov     a, r1
@@ -112,11 +144,11 @@ ___fsdiv:
        subb    a, #0           // carry==0 if mant1 >= mant2
 
 #ifdef FLOAT_FULL_ACCURACY
-       djnz    b, 00011$
+       djnz    b, 00013$
        sjmp    00015$
-00011$:
+00013$:
 #endif
-       jc      00012$
+       jc      00014$
        // subtract
        mov     a, r1
        subb    a, r5
@@ -132,7 +164,7 @@ ___fsdiv:
        mov     r4, a
        clr     c
 
-00012$:
+00014$:
        // shift result
        cpl     c
        mov     a, r0
@@ -161,10 +193,10 @@ ___fsdiv:
        mov     r4, a
 
 #ifdef FLOAT_FULL_ACCURACY
-       sjmp    00010$
+       sjmp    00012$
 00015$:
 #else
-       djnz    b, 00010$
+       djnz    b, 00012$
 #endif
 
        // now we've got a division result, so all we need to do
@@ -185,6 +217,7 @@ ___fsdiv:
        pop     exp_a
        jnc     00016$
        inc     exp_a
+       // incrementing exp_a without checking carry is dangerous
        mov     r4, #0x80
 00016$:
 #else
@@ -198,14 +231,11 @@ ___fsdiv:
 
        lcall   fs_normalize_a
        ljmp    fs_zerocheck_return
-       _endasm;
+       __endasm;
 }
 
 #else
 
-
-
-
 /*
 ** libgcc support for software floating point.
 ** Copyright (C) 1991 by Pipeline Associates, Inc.  All rights reserved.
@@ -224,7 +254,6 @@ ___fsdiv:
 
 /* (c)2000/2001: hacked a little by johan.knol@iduna.nl for sdcc */
 
-
 union float_long
   {
     float f;
@@ -238,7 +267,7 @@ float __fsdiv (float a1, float a2)
   volatile long result;
   volatile unsigned long mask;
   volatile long mant1, mant2;
-  volatile int exp ;
+  volatile int exp;
   char sign;
 
   fl1.f = a1;
@@ -254,8 +283,10 @@ float __fsdiv (float a1, float a2)
 
   /* divide by zero??? */
   if (!fl2.l)
-    /* return NaN or -NaN */
-    return (-1.0);
+    {/* return NaN or -NaN */
+      fl2.l = 0x7FC00000;
+      return (fl2.f);
+    }
 
   /* numerator zero??? */
   if (!fl1.l)
@@ -296,9 +327,13 @@ float __fsdiv (float a1, float a2)
   result &= ~HIDDEN;
 
   /* pack up and go home */
-  fl1.l = PACK (sign ? 1ul<<31 : 0, (unsigned long) exp, result);
+  if (exp >= 0x100)
+    fl1.l = (sign ? SIGNBIT : 0) | __INFINITY;
+  else if (exp < 0)
+    fl1.l = 0;
+  else
+    fl1.l = PACK (sign ? SIGNBIT : 0 , exp, result);
   return (fl1.f);
 }
 
 #endif
-