1 /*-------------------------------------------------------------------------
2 _fsget2args.c - Floating point library in optimized assembly for 8051
3
4 Copyright (c) 2004, Paul Stoffregen, paul@pjrc.com
5
6 This library is free software; you can redistribute it and/or modify it
7 under the terms of the GNU General Public License as published by the
8 Free Software Foundation; either version 2, or (at your option) any
9 later version.
10
11 This library is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
15
16 You should have received a copy of the GNU General Public License
17 along with this library; see the file COPYING. If not, write to the
18 Free Software Foundation, 51 Franklin Street, Fifth Floor, Boston,
19 MA 02110-1301, USA.
20
21 As a special exception, if you link this library with other files,
22 some of which are compiled with SDCC, to produce an executable,
23 this library does not by itself cause the resulting executable to
24 be covered by the GNU General Public License. This exception does
25 not however invalidate any other reasons why the executable file
26 might be covered by the GNU General Public License.
27 -------------------------------------------------------------------------*/
28
29
30
31 #define __SDCC_FLOAT_LIB
32 #include <float.h>
33
34
35 #ifdef FLOAT_ASM_MCS51
36
dummy(void)37 static void dummy(void) __naked
38 {
39 // arg1: passed in a,b,dph,dpl
40 // arg2: passed on stack
41 __asm
42 .globl fsgetargs
43 fsgetargs:
44 // extract the two inputs, placing them into:
45 // sign exponent mantissa
46 // ---- -------- --------
47 // a: sign_a exp_a r4/r3/r2
48 // b: sign_b exp_b r7/r6/r5
49 //
50 mov r2, dpl
51 mov r3, dph
52 mov c, b.7
53 rlc a
54 mov sign_a, c
55 mov exp_a, a
56 jz 00001$
57 setb b.7
58 00001$:
59 mov r4, b
60 // now extract the 2nd parameter from the stack
61 mov a, sp
62 add a, #249
63 mov r0, a
64 mov a, @r0
65 mov r5, a
66 inc r0
67 mov a, @r0
68 mov r6, a
69 inc r0
70 mov b, @r0
71 inc r0
72 mov a, @r0
73 mov c, b.7
74 rlc a
75 mov sign_b, c
76 mov exp_b, a
77 jz 00002$
78 setb b.7
79 00002$:
80 mov r7, b
81 ret
82 __endasm;
83 }
84
85 #endif
86