浮点数和16进制的相互转换工具

shane007

在很多图片字库的游戏里用到了浮点数，这个转换工具也许会派上用处。
* b8 p( ?* O  T+ h3 v$ Z工具是我用C代码自己编译的。

原文
http://www.cs.cornell.edu/~tomf/notes/cps104/floating.html

Helper Software
If you're interested in investigating further, I include two programs for which I provide the C code that you can run to gain a greater understanding of how floating point works, and also to check your work on various assignments.

Hex 2 Float
( w% W  r* [/ I0 Q5 M9 m#include <stdio.h>
( _' Z* o+ s4 Q# e0 ?/ U6 ]
. g3 @! i0 f1 E: s/ w% ?7 H) lint main()
{
+ f) h9 C% ]1 K- X; _  float theFloat;
  while (1) {
% s( o1 u0 I. ?; E$ a+ g    scanf("%x", (int *) &theFloat);
- m& x  p# |5 c2 D$ h    printf("0x%08X, %f\n", *(int *)&theFloat, theFloat);
4 j0 X( k5 x2 C2 |1 e  }
  return 0;
) a5 Y6 O3 z1 z}

* E9 m4 z- d* h4 YThis program accepts as input a hexadecimal quantity and reads it as raw data into the variable "theFloat." The program then outputs the hexadecimal representation of the data in "theFloat" (repeating the input), and prints alongside it the floating point quantity that it represents.

1 z: W: X/ Y2 w$ GI show here a sample run of the program. Notice the special case floating point quantities (0, infinity, and not a number).

For the denormalized but nonzero numbers, this program will display zero even though the number is not really zero. If you want to get around this problem, replace the %f in the formatting string of the printf function with %e, which will deplay the number to great precision with scientific notation. I did not have it as %e because I find scientific notation extremely annoying.
: R; C* ?6 k( K9 G3 l( @+ D
C0B40000
0xC0B40000, -5.625000
2 [6 n, E1 B% C& _1 i2 T43A4B200
0x43A4B200, 329.390625
00000000
2 A# ^- a2 t1 A! }0x00000000, 0.000000
0 W* {+ S; Z  U6 f1 Y& [, Y* I1 @9 E80000000
# [- B! s! H0 h/ }! F0x80000000, -0.000000
$ |, O/ i4 D2 o, U7f800000
4 W6 ^: I! [$ |4 Y9 M( P/ R0x7F800000, inf
- K4 u% Q  m- w$ m! f2 B+ Mff800000
0xFF800000, -inf
8 R" _# p& q/ I+ p( l2 A7fffffff
0x7FFFFFFF, NaN
3 R' `* y' m1 h/ {- e, _( c- uffffffff
0xFFFFFFFF, NaN
7f81A023
3 n* w( G3 {- Z2 h% Q' s- h0x7F81A023, NaN
  N9 u, a2 V0 p9 \# o5 x, s) C' M
Float 2 Hex
#include <stdio.h>
5 D5 n+ _1 n& \$ k. V3 x; _
* H# G& {4 |. Zint main()
{
  float theFloat;
+ Y. c7 X0 Z8 z+ |8 A6 p6 @; v  while (1) {
    scanf("%f", &theFloat);
    printf("0x%08X, %f\n", *(int *)&theFloat, theFloat);
6 l" q9 w; S5 ?  }
6 v* x% a# J& I- }  return 0;
}

This is a slight modification of the "Hex 2 Float" program. The exception is it reads in a floating point number. Just like and outputs the hexadecimal form plus the floating point number. Again I include a sample run of this program, confirming the results of the example problems I covered earlier in this text, along with some other simple cases. Notice the hexadecimal representation of 0.2.

# b1 l9 k3 b3 \4 J& ?$ }% o-5.625
0xC0B40000, -5.625000
329.390625
0x43A4B200, 329.390625
0
0x00000000, 0.000000
-0
* A) P' x* O( F# N: d- V0x80000000, -0.000000
.2
0x3E4CCCCD, 0.200000
: ^  s! ~, N2 i. `( u8 K.5
; k. C5 |3 A& Q& w7 D! G0x3F000000, 0.500000
2 p+ e( F4 G' H* D  n/ V( u; n+ w1
0x3F800000, 1.000000

xll

多谢楼主，我来看看 [s:45]

xll

正需要 [s:42]