Added mcs51 assembly float lib functions (add, sub, mul, div

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

diff --git a/device/lib/_fsadd.c b/device/lib/_fsadd.c
index 5da97f0e947658747b0a08553ee2f9df9aad4b49..8d3c6ab3acd4cd9970139fdb0886e2e7cacd2851 100644 (file)
--- a/device/lib/_fsadd.c
+++ b/device/lib/_fsadd.c
@@ -1,3 +1,139 @@
+/* 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 __fsadd (float a, float b) reentrant
+static void dummy(void) _naked
+{
+       _asm
+
+       // 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
+       //
+       // r1: used to extend precision of a's mantissa
+       // r0: general purpose loop counter
+
+       .globl  ___fsadd
+___fsadd:
+       lcall   fsgetargs
+
+       .globl  fsadd_direct_entry
+fsadd_direct_entry:
+       // we're going to extend mantissa to 32 bits temporarily
+       mov     r1, #0
+
+       // which exponent is greater?
+       mov     a, exp_b
+       cjne    a, exp_a, 00005$
+       sjmp    00011$
+00005$:        jnc     00010$
+
+       // a's exponent was greater, so shift b's mantissa
+       lcall   fs_swap_a_b
+
+00010$:
+       // b's exponent was greater, so shift a's mantissa
+       mov     a, exp_b
+       clr     c
+       subb    a, exp_a
+       lcall   fs_rshift_a     // acc has # of shifts to do
+
+00011$:
+       // decide if we need to add or subtract
+       // sign_a and sign_b are stored in the flag bits of psw,
+       // so this little trick checks if the arguements ave the
+       // same sign.
+       mov     a, psw
+       swap    a
+       xrl     a, psw
+       jb      acc.1, 00022$
+
+00020$:
+       // add the mantissas (both positive or both negative)
+       mov     a, r2
+       add     a, r5
+       mov     r2, a
+       mov     a, r3
+       addc    a, r6
+       mov     r3, a
+       mov     a, r4
+       addc    a, r7
+       mov     r4, a
+       // check for overflow past 24 bits
+       jnc     00021$
+       mov     a, #1
+       lcall   fs_rshift_a
+       mov     a, r4
+       orl     a, #0x80
+       mov     r4, a
+00021$:
+       ljmp    fs_round_and_return
+
+
+
+00022$:
+       // subtract the mantissas (one of them is negative)
+       clr     c
+       mov     a, r2
+       subb    a, r5
+       mov     r2, a
+       mov     a, r3
+       subb    a, r6
+       mov     r3, a
+       mov     a, r4
+       subb    a, r7
+       mov     r4, a
+       jnc     00025$
+       // if we get a negative result, turn it positive and
+       // flip the sign bit
+       clr     c
+       clr     a
+       subb    a, r1
+       mov     r1, a
+       clr     a
+       subb    a, r2
+       mov     r2, a
+       clr     a
+       subb    a, r3
+       mov     r3, a
+       clr     a
+       subb    a, r4
+       mov     r4, a
+       cpl     sign_a
+00025$:
+       lcall   fs_normalize_a
+       ljmp    fs_round_and_return
+
+       _endasm;
+}
+
+#else
+
+
 /*
 ** libgcc support for software floating point.
 ** Copyright (C) 1991 by Pipeline Associates, Inc.  All rights reserved.
@@ -14,7 +150,6 @@
 ** uunet!motown!pipeline!phw
 */
 
-#include <float.h>
 
 union float_long
   {
@@ -96,3 +231,6 @@ float __fsadd (float a1, float a2)
 
   return (fl1.f);
 }
+
+#endif
+