162306a36Sopenharmony_ci/* SPDX-License-Identifier: GPL-2.0 */ 262306a36Sopenharmony_ci/* 362306a36Sopenharmony_ci * arch/alpha/lib/strncat.S 462306a36Sopenharmony_ci * Contributed by Richard Henderson (rth@tamu.edu) 562306a36Sopenharmony_ci * 662306a36Sopenharmony_ci * Append no more than COUNT characters from the null-terminated string SRC 762306a36Sopenharmony_ci * to the null-terminated string DST. Always null-terminate the new DST. 862306a36Sopenharmony_ci * 962306a36Sopenharmony_ci * This differs slightly from the semantics in libc in that we never write 1062306a36Sopenharmony_ci * past count, whereas libc may write to count+1. This follows the generic 1162306a36Sopenharmony_ci * implementation in lib/string.c and is, IMHO, more sensible. 1262306a36Sopenharmony_ci */ 1362306a36Sopenharmony_ci#include <linux/export.h> 1462306a36Sopenharmony_ci .text 1562306a36Sopenharmony_ci 1662306a36Sopenharmony_ci .align 3 1762306a36Sopenharmony_ci .globl strncat 1862306a36Sopenharmony_ci .ent strncat 1962306a36Sopenharmony_cistrncat: 2062306a36Sopenharmony_ci .frame $30, 0, $26 2162306a36Sopenharmony_ci .prologue 0 2262306a36Sopenharmony_ci 2362306a36Sopenharmony_ci mov $16, $0 # set up return value 2462306a36Sopenharmony_ci beq $18, $zerocount 2562306a36Sopenharmony_ci 2662306a36Sopenharmony_ci /* Find the end of the string. */ 2762306a36Sopenharmony_ci 2862306a36Sopenharmony_ci ldq_u $1, 0($16) # load first quadword ($16 may be misaligned) 2962306a36Sopenharmony_ci lda $2, -1($31) 3062306a36Sopenharmony_ci insqh $2, $16, $2 3162306a36Sopenharmony_ci andnot $16, 7, $16 3262306a36Sopenharmony_ci or $2, $1, $1 3362306a36Sopenharmony_ci cmpbge $31, $1, $2 # bits set iff byte == 0 3462306a36Sopenharmony_ci bne $2, $found 3562306a36Sopenharmony_ci 3662306a36Sopenharmony_ci$loop: ldq $1, 8($16) 3762306a36Sopenharmony_ci addq $16, 8, $16 3862306a36Sopenharmony_ci cmpbge $31, $1, $2 3962306a36Sopenharmony_ci beq $2, $loop 4062306a36Sopenharmony_ci 4162306a36Sopenharmony_ci$found: negq $2, $3 # clear all but least set bit 4262306a36Sopenharmony_ci and $2, $3, $2 4362306a36Sopenharmony_ci 4462306a36Sopenharmony_ci and $2, 0xf0, $3 # binary search for that set bit 4562306a36Sopenharmony_ci and $2, 0xcc, $4 4662306a36Sopenharmony_ci and $2, 0xaa, $5 4762306a36Sopenharmony_ci cmovne $3, 4, $3 4862306a36Sopenharmony_ci cmovne $4, 2, $4 4962306a36Sopenharmony_ci cmovne $5, 1, $5 5062306a36Sopenharmony_ci addq $3, $4, $3 5162306a36Sopenharmony_ci addq $16, $5, $16 5262306a36Sopenharmony_ci addq $16, $3, $16 5362306a36Sopenharmony_ci 5462306a36Sopenharmony_ci /* Now do the append. */ 5562306a36Sopenharmony_ci 5662306a36Sopenharmony_ci bsr $23, __stxncpy 5762306a36Sopenharmony_ci 5862306a36Sopenharmony_ci /* Worry about the null termination. */ 5962306a36Sopenharmony_ci 6062306a36Sopenharmony_ci zapnot $1, $27, $2 # was last byte a null? 6162306a36Sopenharmony_ci bne $2, 0f 6262306a36Sopenharmony_ci ret 6362306a36Sopenharmony_ci 6462306a36Sopenharmony_ci0: cmplt $27, $24, $2 # did we fill the buffer completely? 6562306a36Sopenharmony_ci or $2, $18, $2 6662306a36Sopenharmony_ci bne $2, 2f 6762306a36Sopenharmony_ci 6862306a36Sopenharmony_ci and $24, 0x80, $2 # no zero next byte 6962306a36Sopenharmony_ci bne $2, 1f 7062306a36Sopenharmony_ci 7162306a36Sopenharmony_ci /* Here there are bytes left in the current word. Clear one. */ 7262306a36Sopenharmony_ci addq $24, $24, $24 # end-of-count bit <<= 1 7362306a36Sopenharmony_ci2: zap $1, $24, $1 7462306a36Sopenharmony_ci stq_u $1, 0($16) 7562306a36Sopenharmony_ci ret 7662306a36Sopenharmony_ci 7762306a36Sopenharmony_ci1: /* Here we must read the next DST word and clear the first byte. */ 7862306a36Sopenharmony_ci ldq_u $1, 8($16) 7962306a36Sopenharmony_ci zap $1, 1, $1 8062306a36Sopenharmony_ci stq_u $1, 8($16) 8162306a36Sopenharmony_ci 8262306a36Sopenharmony_ci$zerocount: 8362306a36Sopenharmony_ci ret 8462306a36Sopenharmony_ci 8562306a36Sopenharmony_ci .end strncat 8662306a36Sopenharmony_ci EXPORT_SYMBOL(strncat) 87