mirror of
https://github.com/adtools/clib2.git
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66303e9ba2
with the library yet. - The byteswap code was contributed by Peter Bengtsson. Thank you very much! git-svn-id: file:///Users/olsen/Code/migration-svn-zu-git/logical-line-staging/clib2/trunk@15163 87f5fb63-7c3d-0410-a384-fd976d0f7a62
184 lines
5.2 KiB
C
184 lines
5.2 KiB
C
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#ifndef __BYTESWAP_H
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#define __BYTESWAP_H
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#include <sys/types.h>
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#include <stdint.h>
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#if defined(__GNUC__)
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#define __CONST_FUNC __attribute__((const))
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#else
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#define __CONST_FUNC /* Nothing */
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#endif
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/* Single value byteswap functions. */
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extern __CONST_FUNC uint16_t bswap16(uint16_t);
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extern __CONST_FUNC uint32_t bswap24(uint32_t);
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extern __CONST_FUNC uint32_t bswap32(uint32_t);
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#ifdef INT64_MIN
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extern __CONST_FUNC uint64_t bswap64(uint64_t);
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#endif
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/* Block byteswap functions. The swab() function usually resides in unistd.h, so perhaps it should be moved there? */
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/* NOTE: Contrary to the standard swab(), this version returns the "to" pointer and the pointers are not restrict
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* qualified - so swapping buffer-contents in-place is supported.
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* Also, swab24(), swab32() and swab64() are non-standard functions.
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*/
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extern void *swab(void *from,void *to,ssize_t nbytes);
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extern void *swab24(void *from,void *to,ssize_t nbytes); /* Same as swab(), but operates on 24-bit words instead. */
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extern void *swab32(void *from,void *to,ssize_t nbytes); /* Same as swab(), but operates on 32-bit words instead. */
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extern void *swab64(void *from,void *to,ssize_t nbytes); /* Same as swab(), but operates on 64-bit words instead. */
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#define swab16(x) swab(x)
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/*
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* Optimized inline-versions for the single-value functions follow.
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* Only GCC+PPC and GCC+m68k support for now.
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*/
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#if defined(__GNUC__)
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/* Select implementation. */
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#define bswap16(x) (__builtin_constant_p(x))?__const_swap16(x):__swap16(x)
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#define bswap24(x) (__builtin_constant_p(x))?__const_swap24(x):__swap24(x)
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#define bswap32(x) (__builtin_constant_p(x))?__const_swap32(x):__swap32(x)
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#define bswap64(x) (__builtin_constant_p(x))?__const_swap64(x):__swap64(x)
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/* Assembler implementations */
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#if defined(__PPC__)
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static __inline__ __CONST_FUNC uint16_t __swap16(uint16_t u16) {
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uint_fast16_t result;
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__asm__("\
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rlwinm %[result],%[u16],8,16,24\n\
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rlwimi %[result],%[u16],24,24,31\n\
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":[result]"=&r"(result):[u16]"r"(u16));
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return(result);
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}
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static __inline__ __CONST_FUNC uint32_t __swap24(uint32_t u32) {
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uint_fast32_t result;
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__asm__("\
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rlwinm %[result],%[u32],16,8,31\n\
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rlwimi %[result],%[u32],0,16,24\n\
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":[result]"=&r"(result):[u32]"r"(u32));
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return(result);
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}
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static __inline__ __CONST_FUNC uint32_t __swap32(uint32_t u32) {
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uint_fast32_t result;
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__asm__("\
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rlwinm %[result],%[u32],8,8,31\n\
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rlwimi %[result],%[u32],24,0,7\n\
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rlwimi %[result],%[u32],24,16,23\n\
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":[result]"=&r"(result):[u32]"r"(u32));
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return(result);
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}
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/*
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* Note: __swap64() might perhaps be optimized a bit more by scheduling the
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* instructions to alternate register-use, but this instead means there
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* are two less registers free since "u64" and "result" may no longer overlap.
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* Decisions, decisions....
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*/
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static __inline__ __CONST_FUNC uint64_t __swap64(uint64_t u64) {
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uint_fast64_t result;
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uint_fast32_t tmp;
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__asm__("\
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rlwinm %[tmp],%[u64],8,8,31\n\
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rlwimi %[tmp],%[u64],24,0,7\n\
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rlwimi %[tmp],%[u64],24,16,23\n\
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rlwinm %[result],%L[u64],8,8,31\n\
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rlwimi %[result],%L[u64],24,0,7\n\
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rlwimi %[result],%L[u64],24,16,23\n\
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or %L[result],%[tmp],%[tmp]\n\
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":[result]"=r"(result),[tmp]"=&r"(tmp):[u64]"r"(u64));
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return(result);
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}
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#elif defined(__mc68020__)
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static __inline__ __CONST_FUNC uint16_t __swap16(uint16_t u16) {
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__asm__("\
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rol.w #8,%[u16]\n\
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":[u16]"+d"(u16)::"cc");
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return(u16);
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}
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static __inline__ __CONST_FUNC uint32_t __swap24(uint32_t u32) {
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__asm__("\
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rol.w #8,%[u32]\n\
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swap %[u32]\n\
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rol.w #8,%[u32]\n\
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ror.l #8,%[u32]\n\
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":[u32]"+d"(u32)::"cc");
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return(u32);
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}
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static __inline__ __CONST_FUNC uint32_t __swap32(uint32_t u32) {
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__asm__("\
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rol.w #8,%[u32]\n\
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swap %[u32]\n\
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rol.w #8,%[u32]\n\
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":[u32]"+d"(u32)::"cc");
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return(u32);
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}
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static __inline__ __CONST_FUNC uint64_t __swap64(uint64_t u64) {
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__asm__("\
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rol.w #8,%[u64]\n\
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rol.w #8,%L[u64]\n\
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swap %[u64]\n\
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swap %L[u64]\n\
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rol.w #8,%[u64]\n\
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rol.w #8,%L[u64]\n\
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exg %[u64],L%[u64]\n\
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":[u64]"+d"(u64)::"cc");
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return(u64);
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}
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#else
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/* Unknown or undefined architecture. Perhaps compiling with "-strict -ansi", but should not use this header then anyway. */
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#undef bswap16
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#undef bswap24
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#undef bswap32
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#undef bswap64
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#define bswap16(x) (__builtin_constant_p(x))?__const_swap16(x):bswap16(x)
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#define bswap24(x) (__builtin_constant_p(x))?__const_swap24(x):bswap24(x)
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#define bswap32(x) (__builtin_constant_p(x))?__const_swap32(x):bswap32(x)
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#define bswap64(x) (__builtin_constant_p(x))?__const_swap64(x):bswap64(x)
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#endif
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/* C implementations for constant values */
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static __inline__ uint16_t __const_swap16(uint16_t u16) {
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return(u16>>8|u16<<8);
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}
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static __inline__ uint32_t __const_swap24(uint32_t u32) {
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return(((u32&0xff)<<16)|((u32&0xff00))|((u32&0xff0000)>>16));
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}
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static __inline__ uint32_t __const_swap32(uint32_t u32) {
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return(((u32&0xff)<<24)|((u32&0xff00)<<8)|((u32&0xff0000)>>8)|((u32&0xff000000)>>24));
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}
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static __inline__ uint64_t __const_swap64(uint64_t u64) {
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return(((u64&0xffLL)<<56)|((u64&0xff00LL)<<40)|((u64&0xff0000LL)<<24)|((u64&0xff000000LL)<<8)|
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((u64&0xff00000000LL)>>8)|((u64&0xff0000000000LL)>>24)|((u64&0xff000000000000LL)>>40)|((u64&0xff00000000000000LL)>>56));
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}
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#endif /* __GNUC__ */
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#endif /* __BYTESWAP_H */
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/* vi:set ts=3: */
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