+/* Floating point library in optimized assembly for 8051
+ * Copyright (c) 2004, Paul Stoffregen, paul@pjrc.com
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ */
+
+
+#define SDCC_FLOAT_LIB
+#include <float.h>
+
+
+#ifdef FLOAT_ASM_MCS51
+
+// float __fsdiv (float a, float b) __reentrant
+static void dummy(void) __naked
+{
+ __asm
+ .globl ___fsdiv
+___fsdiv:
+ // extract the two inputs, placing them into:
+ // sign exponent mantiassa
+ // ---- -------- ---------
+ // a: sign_a exp_a r4/r3/r2
+ // b: sign_b exp_b r7/r6/r5
+
+ lcall fsgetargs
+
+ // compute final sign bit
+ jnb sign_b, 00001$
+ cpl sign_a
+00001$:
+
+ // if divisor is zero, ...
+ cjne r7, #0, 00003$
+ // 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, 00004$
+ ljmp fs_return_zero
+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$:
+
+ // subtract exponents
+ clr c
+ subb a, exp_b
+ // if no carry then no underflow
+ jnc 00008$
+ add a, #127
+ jc 00009$
+ ljmp fs_return_zero
+
+00008$:
+ add a, #128
+ dec a
+ jnc 00009$
+ ljmp fs_return_inf
+
+00009$:
+ mov exp_a, a
+
+ // need extra bits on a's mantissa
+#ifdef FLOAT_FULL_ACCURACY
+ clr c
+ mov a, r5
+ subb a, r2
+ mov a, r6
+ subb a, r3
+ mov a, r7
+ subb a, r4
+ jc 00010$
+ dec exp_a
+ clr c
+ mov a, r2
+ rlc a
+ mov r1, a
+ mov a, r3
+ rlc a
+ mov r2, a
+ mov a, r4
+ rlc a
+ mov r3, a
+ clr a
+ rlc a
+ mov r4, a
+ sjmp 00011$
+00010$:
+#endif
+ clr a
+ xch a, r4
+ xch a, r3
+ xch a, r2
+ mov r1, a
+00011$:
+
+ // begin long division
+ push exp_a
+#ifdef FLOAT_FULL_ACCURACY
+ mov b, #25
+#else
+ mov b, #24
+#endif
+00012$:
+ // compare
+ clr c
+ mov a, r1
+ subb a, r5
+ mov a, r2
+ subb a, r6
+ mov a, r3
+ subb a, r7
+ mov a, r4
+ subb a, #0 // carry==0 if mant1 >= mant2
+
+#ifdef FLOAT_FULL_ACCURACY
+ djnz b, 00013$
+ sjmp 00015$
+00013$:
+#endif
+ jc 00014$
+ // subtract
+ mov a, r1
+ subb a, r5
+ mov r1, a
+ mov a, r2
+ subb a, r6
+ mov r2, a
+ mov a, r3
+ subb a, r7
+ mov r3, a
+ mov a, r4
+ subb a, #0
+ mov r4, a
+ clr c
+
+00014$:
+ // shift result
+ cpl c
+ mov a, r0
+ rlc a
+ mov r0, a
+ mov a, dpl
+ rlc a
+ mov dpl, a
+ mov a, dph
+ rlc a
+ mov dph, a
+
+ // shift partial remainder
+ clr c
+ mov a, r1
+ rlc a
+ mov r1, a
+ mov a, r2
+ rlc a
+ mov r2, a
+ mov a, r3
+ rlc a
+ mov r3, a
+ mov a, r4
+ rlc a
+ mov r4, a
+
+#ifdef FLOAT_FULL_ACCURACY
+ sjmp 00012$
+00015$:
+#else
+ djnz b, 00012$
+#endif
+
+ // now we've got a division result, so all we need to do
+ // is round off properly, normalize and output a float
+
+#ifdef FLOAT_FULL_ACCURACY
+ cpl c
+ clr a
+ mov r1, a
+ addc a, r0
+ mov r2, a
+ clr a
+ addc a, dpl
+ mov r3, a
+ clr a
+ addc a, dph
+ mov r4, a
+ pop exp_a
+ jnc 00016$
+ inc exp_a
+ // incrementing exp_a without checking carry is dangerous
+ mov r4, #0x80
+00016$:
+#else
+ mov r1, #0
+ mov a, r0
+ mov r2, a
+ mov r3, dpl
+ mov r4, dph
+ pop exp_a
+#endif
+
+ lcall fs_normalize_a
+ ljmp fs_zerocheck_return
+ __endasm;
+}
+
+#else
+
/*
** libgcc support for software floating point.
** Copyright (C) 1991 by Pipeline Associates, Inc. All rights reserved.
** I would appreciate receiving any updates/patches/changes that anyone
** makes, and am willing to be the repository for said changes (am I
** making a big mistake?).
-
-Warning! Only single-precision is actually implemented. This file
-won't really be much use until double-precision is supported.
-
-However, once that is done, this file might eventually become a
-replacement for libgcc1.c. It might also make possible
-cross-compilation for an IEEE target machine from a non-IEEE
-host such as a VAX.
-
-If you'd like to work on completing this, please talk to rms@gnu.ai.mit.edu.
-
-
**
** Pat Wood
** Pipeline Associates, Inc.
** pipeline!phw@motown.com or
** sun!pipeline!phw or
** uunet!motown!pipeline!phw
-**
-** 05/01/91 -- V1.0 -- first release to gcc mailing lists
-** 05/04/91 -- V1.1 -- added float and double prototypes and return values
-** -- fixed problems with adding and subtracting zero
-** -- fixed rounding in truncdfsf2
-** -- fixed SWAP define and tested on 386
*/
-/*
-** The following are routines that replace the libgcc soft floating point
-** routines that are called automatically when -msoft-float is selected.
-** The support single and double precision IEEE format, with provisions
-** for byte-swapped machines (tested on 386). Some of the double-precision
-** routines work at full precision, but most of the hard ones simply punt
-** and call the single precision routines, producing a loss of accuracy.
-** long long support is not assumed or included.
-** Overall accuracy is close to IEEE (actually 68882) for single-precision
-** arithmetic. I think there may still be a 1 in 1000 chance of a bit
-** being rounded the wrong way during a multiply. I'm not fussy enough to
-** bother with it, but if anyone is, knock yourself out.
-**
-** Efficiency has only been addressed where it was obvious that something
-** would make a big difference. Anyone who wants to do this right for
-** best speed should go in and rewrite in assembler.
-**
-** I have tested this only on a 68030 workstation and 386/ix integrated
-** in with -msoft-float.
-*/
-
-/* the following deal with IEEE single-precision numbers */
-#define EXCESS 126
-#define SIGNBIT ((unsigned long)0x80000000)
-#define HIDDEN (unsigned long)(1 << 23)
-#define SIGN(fp) ((fp >> (8*sizeof(fp)-1)) & 1)
-#define EXP(fp) (((fp) >> 23) & (unsigned int)0x00FF)
-#define MANT(fp) (((fp) & (unsigned long)0x007FFFFF) | HIDDEN)
-#define PACK(s,e,m) ((s) | ((e) << 23) | (m))
+/* (c)2000/2001: hacked a little by johan.knol@iduna.nl for sdcc */
union float_long
{
};
/* divide two floats */
-float
-__fsdiv (float a1, float a2)
+float __fsdiv (float a1, float a2)
{
volatile union float_long fl1, fl2;
volatile long result;
volatile unsigned long mask;
volatile long mant1, mant2;
- volatile int exp ;
+ volatile int exp;
char sign;
fl1.f = a1;
/* 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)
result &= ~HIDDEN;
/* pack up and go home */
- fl1.l = PACK (sign, (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
projects / fw / sdcc / blobdiff