1 /* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ 2 #ifndef _ALPHA_SWAB_H 3 #define _ALPHA_SWAB_H 4 5 #include <linux/types.h> 6 #include <linux/compiler.h> 7 #include <asm/compiler.h> 8 9 #ifdef __GNUC__ 10 11 static inline __attribute_const__ __u32 __arch_swab32(__u32 x) 12 { 13 /* 14 * Unfortunately, we can't use the 6 instruction sequence 15 * on ev6 since the latency of the UNPKBW is 3, which is 16 * pretty hard to hide. Just in case a future implementation 17 * has a lower latency, here's the sequence (also by Mike Burrows) 18 * 19 * UNPKBW a0, v0 v0: 00AA00BB00CC00DD 20 * SLL v0, 24, a0 a0: BB00CC00DD000000 21 * BIS v0, a0, a0 a0: BBAACCBBDDCC00DD 22 * EXTWL a0, 6, v0 v0: 000000000000BBAA 23 * ZAP a0, 0xf3, a0 a0: 00000000DDCC0000 24 * ADDL a0, v0, v0 v0: ssssssssDDCCBBAA 25 */ 26 27 __u64 t0, t1, t2, t3; 28 29 t0 = __kernel_inslh(x, 7); /* t0 : 0000000000AABBCC */ 30 t1 = __kernel_inswl(x, 3); /* t1 : 000000CCDD000000 */ 31 t1 |= t0; /* t1 : 000000CCDDAABBCC */ 32 t2 = t1 >> 16; /* t2 : 0000000000CCDDAA */ 33 t0 = t1 & 0xFF00FF00; /* t0 : 00000000DD00BB00 */ 34 t3 = t2 & 0x00FF00FF; /* t3 : 0000000000CC00AA */ 35 t1 = t0 + t3; /* t1 : ssssssssDDCCBBAA */ 36 37 return t1; 38 } 39 #define __arch_swab32 __arch_swab32 40 41 #endif /* __GNUC__ */ 42 43 #endif /* _ALPHA_SWAB_H */ 44