1 /* 2 * Copyright (C) 2011 Tobias Klauser <tklauser@distanz.ch> 3 * Copyright (C) 2004 Microtronix Datacom Ltd 4 * 5 * This file is subject to the terms and conditions of the GNU General Public 6 * License. See the file "COPYING" in the main directory of this archive 7 * for more details. 8 */ 9 10 #include <linux/types.h> 11 #include <linux/string.h> 12 13 void *memset(void *s, int c, size_t count) 14 { 15 int destptr, charcnt, dwordcnt, fill8reg, wrkrega; 16 17 if (!count) 18 return s; 19 20 c &= 0xFF; 21 22 if (count <= 8) { 23 char *xs = (char *) s; 24 25 while (count--) 26 *xs++ = c; 27 return s; 28 } 29 30 __asm__ __volatile__ ( 31 /* fill8 %3, %5 (c & 0xff) */ 32 " slli %4, %5, 8\n" 33 " or %4, %4, %5\n" 34 " slli %3, %4, 16\n" 35 " or %3, %3, %4\n" 36 /* Word-align %0 (s) if necessary */ 37 " andi %4, %0, 0x01\n" 38 " beq %4, zero, 1f\n" 39 " addi %1, %1, -1\n" 40 " stb %3, 0(%0)\n" 41 " addi %0, %0, 1\n" 42 "1: mov %2, %1\n" 43 /* Dword-align %0 (s) if necessary */ 44 " andi %4, %0, 0x02\n" 45 " beq %4, zero, 2f\n" 46 " addi %1, %1, -2\n" 47 " sth %3, 0(%0)\n" 48 " addi %0, %0, 2\n" 49 " mov %2, %1\n" 50 /* %1 and %2 are how many more bytes to set */ 51 "2: srli %2, %2, 2\n" 52 /* %2 is how many dwords to set */ 53 "3: stw %3, 0(%0)\n" 54 " addi %0, %0, 4\n" 55 " addi %2, %2, -1\n" 56 " bne %2, zero, 3b\n" 57 /* store residual word and/or byte if necessary */ 58 " andi %4, %1, 0x02\n" 59 " beq %4, zero, 4f\n" 60 " sth %3, 0(%0)\n" 61 " addi %0, %0, 2\n" 62 /* store residual byte if necessary */ 63 "4: andi %4, %1, 0x01\n" 64 " beq %4, zero, 5f\n" 65 " stb %3, 0(%0)\n" 66 "5:\n" 67 : "=r" (destptr), /* %0 Output */ 68 "=r" (charcnt), /* %1 Output */ 69 "=r" (dwordcnt), /* %2 Output */ 70 "=r" (fill8reg), /* %3 Output */ 71 "=&r" (wrkrega) /* %4 Output only */ 72 : "r" (c), /* %5 Input */ 73 "0" (s), /* %0 Input/Output */ 74 "1" (count) /* %1 Input/Output */ 75 : "memory" /* clobbered */ 76 ); 77 78 return s; 79 } 80