1 /*-------------------------------------------------------------------------
2 _fsreturnval.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 __asm
40
41 .globl fs_round_and_return
42 fs_round_and_return:
43 #ifdef FLOAT_FULL_ACCURACY
44 // discard the extra 8 bits of precision we kept around in r1
45 cjne r1, #128, 00001$
46 mov a, r2
47 rrc a
48 cpl c
49 00001$:
50 jc fs_zerocheck_return
51 mov a, r2
52 add a, #1
53 mov r2, a
54 clr a
55 addc a, r3
56 mov r3, a
57 clr a
58 addc a, r4
59 mov r4, a
60 jnc fs_zerocheck_return
61 mov r4, #0x80
62 inc exp_a
63 #endif
64
65 .globl fs_zerocheck_return
66 fs_zerocheck_return:
67 // zero output is a special case
68 cjne r4, #0, fs_direct_return
69 cjne r3, #0, fs_direct_return
70 cjne r2, #0, fs_direct_return
71
72 .globl fs_return_zero
73 fs_return_zero:
74 clr a
75 mov b, a
76 mov dph, a
77 mov dpl, a
78 ret
79
80 .globl fs_direct_return
81 fs_direct_return:
82 // collect all pieces and return
83 mov c, sign_a
84 mov a, exp_a
85 rrc a
86 mov b, r4
87 mov b.7, c
88 mov dph, r3
89 mov dpl, r2
90 ret
91
92 .globl fs_return_inf
93 fs_return_inf:
94 clr a
95 mov dph, a
96 mov dpl, a
97 mov b, #0x80
98 cpl a
99 mov c, sign_a
100 rrc a
101 ret
102
103 .globl fs_return_nan
104 fs_return_nan:
105 clr a
106 mov dph, a
107 mov dpl, a
108 mov b, #0xC0
109 mov a, #0x7F
110 ret
111
112 __endasm;
113 }
114
115 #endif
116