1 ; fltarith.asm show some simple C code and corresponding nasm code
2 ; the nasm code is one sample, not unique
3 ;
4 ; compile nasm -f elf -l fltarith.lst fltarith.asm
5 ; link gcc -o fltarith fltarith.o
6 ; run fltarith
7 ;
8 ; the output from running fltarith and fltarithc is:
9 ; c=5.0, a=3.000000e+00, b=4.000000e+00, c=5.000000e+00
10 ; c=a+b, a=3.000000e+00, b=4.000000e+00, c=7.000000e+00
11 ; c=a-b, a=3.000000e+00, b=4.000000e+00, c=-1.000000e+00
12 ; c=a*b, a=3.000000e+00, b=4.000000e+00, c=1.200000e+01
13 ; c=c/a, a=3.000000e+00, b=4.000000e+00, c=4.000000e+00
14 ;
15 ;The file fltarith.c is:
16 ; #include <stdio.h>
17 ; int main()
18 ; {
19 ; double a=3.0, b=4.0, c;
20 ;
21 ; c=5.0;
22 ; printf("%s, a=%e, b=%e, c=%e\n","c=5.0", a, b, c);
23 ; c=a+b;
24 ; printf("%s, a=%e, b=%e, c=%e\n","c=a+b", a, b, c);
25 ; c=a-b;
26 ; printf("%s, a=%e, b=%e, c=%e\n","c=a-b", a, b, c);
27 ; c=a*b;
28 ; printf("%s, a=%e, b=%e, c=%e\n","c=a*b", a, b, c);
29 ; c=c/a;
30 ; printf("%s, a=%e, b=%e, c=%e\n","c=c/a", a, b, c);
31 ; return 0;
32 ; }
33
34 extern printf ; the C function to be called
35
36 %macro pabc 1 ; a "simple" print macro
37 section .data
38 .str db %1,0 ; %1 is macro call first actual parameter
39 section .text
40 ; push onto stack backwards
41 push dword [c+4] ; double c (bottom)
42 push dword [c] ; double c
43 push dword [b+4] ; double b (bottom)
44 push dword [b] ; double b
45 push dword [a+4] ; double a (bottom)
46 push dword [a] ; double a
47 push dword .str ; users string
48 push dword fmt ; address of format string
49 call printf ; Call C function
50 add esp,32 ; pop stack 8*4 bytes
51 %endmacro
52
53 section .data ; preset constants, writeable
54 00000000 A3369FAAAAAA0A40 a: dq 3.333333333 ; 64-bit variable a initialized to 3.0
55 00000008 C279BF711CC71140 b: dq 4.444444444 ; 64-bit variable b initializes to 4.0
56 00000010 0000000000001440 five: dq 5.0 ; constant 5.0
57 00000018 25732C20613D25652C- fmt: db "%s, a=%e, b=%e, c=%e",10,0 ; format string for printf
58 00000021 20623D25652C20633D-
59 0000002A 25650A00
60
61 section .bss ; unitialized space
62 00000000 <res 00000008> c: resq 1 ; reserve a 64-bit word
63
64 section .text ; instructions, code segment
65 global main ; for gcc standard linking
66 main: ; label
67
68 lit5: ; c=5.0;
69 00000000 DD05[10000000] fld qword [five] ; 5.0 constant
70 00000006 DD1D[00000000] fstp qword [c] ; store into c
71 pabc "c=5.0" ; invoke the print macro
72 <1> section .data
73 0000002E 633D352E3000 <1> .str db %1,0
74 <1> section .text
75 <1>
76 0000000C FF35[04000000] <1> push dword [c+4]
77 00000012 FF35[00000000] <1> push dword [c]
78 00000018 FF35[0C000000] <1> push dword [b+4]
79 0000001E FF35[08000000] <1> push dword [b]
80 00000024 FF35[04000000] <1> push dword [a+4]
81 0000002A FF35[00000000] <1> push dword [a]
82 00000030 68[2E000000] <1> push dword .str
83 00000035 68[18000000] <1> push dword fmt
84 0000003A E8(00000000) <1> call printf
85 0000003F 83C420 <1> add esp,32
86
87 addb: ; c=a+b;
88 00000042 DD05[00000000] fld qword [a] ; load a (pushed on flt pt stack, st0)
89 00000048 DC05[08000000] fadd qword [b] ; floating add b (to st0)
90 0000004E DD1D[00000000] fstp qword [c] ; store into c (pop flt pt stack)
91 pabc "c=a+b" ; invoke the print macro
92 <1> section .data
93 00000034 633D612B6200 <1> .str db %1,0
94 <1> section .text
95 <1>
96 00000054 FF35[04000000] <1> push dword [c+4]
97 0000005A FF35[00000000] <1> push dword [c]
98 00000060 FF35[0C000000] <1> push dword [b+4]
99 00000066 FF35[08000000] <1> push dword [b]
100 0000006C FF35[04000000] <1> push dword [a+4]
101 00000072 FF35[00000000] <1> push dword [a]
102 00000078 68[34000000] <1> push dword .str
103 0000007D 68[18000000] <1> push dword fmt
104 00000082 E8(00000000) <1> call printf
105 00000087 83C420 <1> add esp,32
106
107 subb: ; c=a-b;
108 0000008A DD05[00000000] fld qword [a] ; load a (pushed on flt pt stack, st0)
109 00000090 DC25[08000000] fsub qword [b] ; floating subtract b (to st0)
110 00000096 DD1D[00000000] fstp qword [c] ; store into c (pop flt pt stack)
111 pabc "c=a-b" ; invoke the print macro
112 <1> section .data
113 0000003A 633D612D6200 <1> .str db %1,0
114 <1> section .text
115 <1>
116 0000009C FF35[04000000] <1> push dword [c+4]
117 000000A2 FF35[00000000] <1> push dword [c]
118 000000A8 FF35[0C000000] <1> push dword [b+4]
119 000000AE FF35[08000000] <1> push dword [b]
120 000000B4 FF35[04000000] <1> push dword [a+4]
121 000000BA FF35[00000000] <1> push dword [a]
122 000000C0 68[3A000000] <1> push dword .str
123 000000C5 68[18000000] <1> push dword fmt
124 000000CA E8(00000000) <1> call printf
125 000000CF 83C420 <1> add esp,32
126
127 mulb: ; c=a*b;
128 000000D2 DD05[00000000] fld qword [a] ; load a (pushed on flt pt stack, st0)
129 000000D8 DC0D[08000000] fmul qword [b] ; floating multiply by b (to st0)
130 000000DE DD1D[00000000] fstp qword [c] ; store product into c (pop flt pt stack)
131 pabc "c=a*b" ; invoke the print macro
132 <1> section .data
133 00000040 633D612A6200 <1> .str db %1,0
134 <1> section .text
135 <1>
136 000000E4 FF35[04000000] <1> push dword [c+4]
137 000000EA FF35[00000000] <1> push dword [c]
138 000000F0 FF35[0C000000] <1> push dword [b+4]
139 000000F6 FF35[08000000] <1> push dword [b]
140 000000FC FF35[04000000] <1> push dword [a+4]
141 00000102 FF35[00000000] <1> push dword [a]
142 00000108 68[40000000] <1> push dword .str
143 0000010D 68[18000000] <1> push dword fmt
144 00000112 E8(00000000) <1> call printf
145 00000117 83C420 <1> add esp,32
146
147 diva: ; c=c/a;
148 0000011A DD05[00000000] fld qword [c] ; load c (pushed on flt pt stack, st0)
149 00000120 DC35[00000000] fdiv qword [a] ; floating divide by a (to st0)
150 00000126 DD1D[00000000] fstp qword [c] ; store quotient into c (pop flt pt stack)
151 pabc "c=c/a" ; invoke the print macro
152 <1> section .data
153 00000046 633D632F6100 <1> .str db %1,0
154 <1> section .text
155 <1>
156 0000012C FF35[04000000] <1> push dword [c+4]
157 00000132 FF35[00000000] <1> push dword [c]
158 00000138 FF35[0C000000] <1> push dword [b+4]
159 0000013E FF35[08000000] <1> push dword [b]
160 00000144 FF35[04000000] <1> push dword [a+4]
161 0000014A FF35[00000000] <1> push dword [a]
162 00000150 68[46000000] <1> push dword .str
163 00000155 68[18000000] <1> push dword fmt
164 0000015A E8(00000000) <1> call printf
165 0000015F 83C420 <1> add esp,32
166
167 00000162 B800000000 mov eax,0 ; exit code, 0=normal
168 00000167 C3 ret ; main returns to operating system
169
170