xref: /titanic_41/usr/src/grub/grub-0.97/netboot/i386_byteswap.h (revision c037192b037119c9fd354732fc29b38ce097d356)
1 #ifndef ETHERBOOT_BITS_BYTESWAP_H
2 #define ETHERBOOT_BITS_BYTESWAP_H
3 
4 #include "types.h"
5 static inline uint16_t __i386_bswap_16(uint16_t x)
6 {
7 	__asm__("xchgb %b0,%h0\n\t"
8 		: "=q" (x)
9 		: "0" (x));
10 	return x;
11 }
12 
13 static inline uint32_t __i386_bswap_32(uint32_t x)
14 {
15 	__asm__("xchgb %b0,%h0\n\t"
16 		"rorl $16,%0\n\t"
17 		"xchgb %b0,%h0"
18 		: "=q" (x)
19 		: "0" (x));
20 	return x;
21 }
22 
23 
24 #define __bswap_constant_16(x) \
25 	((uint16_t)((((uint16_t)(x) & 0x00ff) << 8) | \
26 		(((uint16_t)(x) & 0xff00) >> 8)))
27 
28 #define __bswap_constant_32(x) \
29 	((uint32_t)((((uint32_t)(x) & 0x000000ffU) << 24) | \
30 		(((uint32_t)(x) & 0x0000ff00U) <<  8) | \
31 		(((uint32_t)(x) & 0x00ff0000U) >>  8) | \
32 		(((uint32_t)(x) & 0xff000000U) >> 24)))
33 
34 #define __bswap_16(x) \
35 	(__builtin_constant_p(x) ? \
36 	__bswap_constant_16(x) : \
37 	__i386_bswap_16(x))
38 
39 
40 #define __bswap_32(x) \
41 	(__builtin_constant_p(x) ? \
42 	__bswap_constant_32(x) : \
43 	__i386_bswap_32(x))
44 
45 
46 #endif /* ETHERBOOT_BITS_BYTESWAP_H */
47