1 // Copyright 2014 The Go Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style 3 // license that can be found in the LICENSE file. 4 5 #include "textflag.h" 6 7 // void runtimememclrNoHeapPointers(void*, uintptr) 8 TEXT runtimememclrNoHeapPointers(SB),NOSPLIT,$0-16 9 MOVD ptr+0(FP), R0 10 MOVD n+8(FP), R1 11 // If size is less than 16 bytes, use tail_zero to zero what remains 12 CMP $16, R1 13 BLT tail_zero 14 // Get buffer offset into 16 byte aligned address for better performance 15 ANDS $15, R0, ZR 16 BNE unaligned_to_16 17 aligned_to_16: 18 LSR $4, R1, R2 19 zero_by_16: 20 STP.P (ZR, ZR), 16(R0) 21 SUBS $1, R2, R2 22 BNE zero_by_16 23 24 ANDS $15, R1, R1 25 BEQ ending 26 27 // Zero buffer with size=R1 < 16 28 tail_zero: 29 TBZ $3, R1, tail_zero_4 30 MOVD.P ZR, 8(R0) 31 32 tail_zero_4: 33 TBZ $2, R1, tail_zero_2 34 MOVW.P ZR, 4(R0) 35 36 tail_zero_2: 37 TBZ $1, R1, tail_zero_1 38 MOVH.P ZR, 2(R0) 39 40 tail_zero_1: 41 TBZ $0, R1, ending 42 MOVB ZR, (R0) 43 44 ending: 45 RET 46 47 unaligned_to_16: 48 MOVD R0, R2 49 head_loop: 50 MOVBU.P ZR, 1(R0) 51 ANDS $15, R0, ZR 52 BNE head_loop 53 // Adjust length for what remains 54 SUB R2, R0, R3 55 SUB R3, R1 56 // If size is less than 16 bytes, use tail_zero to zero what remains 57 CMP $16, R1 58 BLT tail_zero 59 B aligned_to_16 60
