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 // +build ppc64 ppc64le 6 7 #include "textflag.h" 8 9 // void runtimememmove(void*, void*, uintptr) 10 TEXT runtimememmove(SB), NOSPLIT|NOFRAME, $0-24 11 MOVD to+0(FP), R3 12 MOVD from+8(FP), R4 13 MOVD n+16(FP), R5 14 15 // Determine if there are doublewords to 16 // copy so a more efficient move can be done 17 check: 18 ANDCC $7, R5, R7 // R7: bytes to copy 19 SRAD $3, R5, R6 // R6: double words to copy 20 CMP R6, $0, CR1 // CR1[EQ] set if no double words to copy 21 22 // Determine overlap by subtracting dest - src and comparing against the 23 // length. The catches the cases where src and dest are in different types 24 // of storage such as stack and static to avoid doing backward move when not 25 // necessary. 26 27 SUB R4, R3, R8 // dest - src 28 CMPU R8, R5, CR2 // < len? 29 BC 12, 8, backward // BLT CR2 backward 30 31 // Copying forward if no overlap. 32 33 BC 12, 6, noforwardlarge // "BEQ CR1, noforwardlarge" 34 MOVD R6,CTR // R6 = number of double words 35 SRADCC $2,R6,R8 // 32 byte chunks? 36 BNE forward32setup // 37 38 // Move double words 39 40 forward8: 41 MOVD 0(R4), R8 // double word 42 ADD $8,R4 43 MOVD R8, 0(R3) // 44 ADD $8,R3 45 BC 16, 0, forward8 46 BR noforwardlarge // handle remainder 47 48 // Prepare for moves of 32 bytes at a time. 49 50 forward32setup: 51 DCBTST (R3) // prepare data cache 52 DCBT (R4) 53 MOVD R8, CTR // double work count 54 55 forward32: 56 MOVD 0(R4), R8 // load 4 double words 57 MOVD 8(R4), R9 58 MOVD 16(R4), R14 59 MOVD 24(R4), R15 60 ADD $32,R4 61 MOVD R8, 0(R3) // store those 4 62 MOVD R9, 8(R3) 63 MOVD R14,16(R3) 64 MOVD R15,24(R3) 65 ADD $32,R3 // bump up for next set 66 BC 16, 0, forward32 // continue 67 RLDCLCC $61,R5,$3,R6 // remaining doublewords 68 BEQ noforwardlarge 69 MOVD R6,CTR // set up the CTR 70 BR forward8 71 72 noforwardlarge: 73 CMP R7,$0 // any remaining bytes 74 BC 4, 1, LR 75 76 forwardtail: 77 MOVD R7, CTR // move tail bytes 78 79 forwardtailloop: 80 MOVBZ 0(R4), R8 // move single bytes 81 ADD $1,R4 82 MOVBZ R8, 0(R3) 83 ADD $1,R3 84 BC 16, 0, forwardtailloop 85 RET 86 87 backward: 88 // Copying backwards proceeds by copying R7 bytes then copying R6 double words. 89 // R3 and R4 are advanced to the end of the destination/source buffers 90 // respectively and moved back as we copy. 91 92 ADD R5, R4, R4 // end of source 93 ADD R3, R5, R3 // end of dest 94 95 BEQ nobackwardtail // earlier condition 96 97 MOVD R7, CTR // bytes to move 98 99 backwardtailloop: 100 MOVBZ -1(R4), R8 // point to last byte 101 SUB $1,R4 102 MOVBZ R8, -1(R3) 103 SUB $1,R3 104 BC 16, 0, backwardtailloop 105 106 nobackwardtail: 107 CMP R6,$0 108 BC 4, 5, LR 109 110 backwardlarge: 111 MOVD R6, CTR 112 113 backwardlargeloop: 114 MOVD -8(R4), R8 115 SUB $8,R4 116 MOVD R8, -8(R3) 117 SUB $8,R3 118 BC 16, 0, backwardlargeloop // 119 RET 120
