sdcc-gas/device/lib/_fsget2args.c

86 lines
2.2 KiB
C

/*-------------------------------------------------------------------------
_fsget2args.c - Floating point library in optimized assembly for 8051
Copyright (c) 2004, Paul Stoffregen, paul@pjrc.com
This library is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by the
Free Software Foundation; either version 2, 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 library; see the file COPYING. If not, write to the
Free Software Foundation, 51 Franklin Street, Fifth Floor, Boston,
MA 02110-1301, USA.
As a special exception, if you link this library with other files,
some of which are compiled with SDCC, to produce an executable,
this library does not by itself cause the resulting executable to
be covered by the GNU General Public License. This exception does
not however invalidate any other reasons why the executable file
might be covered by the GNU General Public License.
-------------------------------------------------------------------------*/
#define __SDCC_FLOAT_LIB
#include <float.h>
#ifdef FLOAT_ASM_MCS51
static void dummy(void) __naked
{
// arg1: passed in a,b,dph,dpl
// arg2: passed on stack
__asm
.globl fsgetargs
fsgetargs:
// extract the two inputs, placing them into:
// sign exponent mantissa
// ---- -------- --------
// a: sign_a exp_a r4/r3/r2
// b: sign_b exp_b r7/r6/r5
//
mov r2, dpl
mov r3, dph
mov c, b.7
rlc a
mov sign_a, c
mov exp_a, a
jz 00001$
setb b.7
00001$:
mov r4, b
// now extract the 2nd parameter from the stack
mov a, sp
add a, #249
mov r0, a
mov a, @r0
mov r5, a
inc r0
mov a, @r0
mov r6, a
inc r0
mov b, @r0
inc r0
mov a, @r0
mov c, b.7
rlc a
mov sign_b, c
mov exp_b, a
jz 00002$
setb b.7
00002$:
mov r7, b
ret
__endasm;
}
#endif