memclr_mipsx.s

     1  // Copyright 2016 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  //go:build mips || mipsle
     6  
     7  #include "textflag.h"
     8  
     9  #ifdef GOARCH_mips
    10  #define MOVWHI  MOVWL
    11  #define MOVWLO  MOVWR
    12  #else
    13  #define MOVWHI  MOVWR
    14  #define MOVWLO  MOVWL
    15  #endif
    16  
    17  // See memclrNoHeapPointers Go doc for important implementation constraints.
    18  
    19  // func memclrNoHeapPointers(ptr unsafe.Pointer, n uintptr)
    20  TEXT runtime·memclrNoHeapPointers(SB),NOSPLIT,$0-8
    21  	MOVW	n+4(FP), R2
    22  	MOVW	ptr+0(FP), R1
    23  
    24  	SGTU	$4, R2, R3
    25  	ADDU	R2, R1, R4
    26  	BNE	R3, small_zero
    27  
    28  ptr_align:
    29  	AND	$3, R1, R3
    30  	BEQ	R3, setup
    31  	SUBU	R1, R0, R3
    32  	AND	$3, R3		// R3 contains number of bytes needed to align ptr
    33  	MOVWHI	R0, 0(R1)	// MOVWHI will write zeros up to next word boundary
    34  	SUBU	R3, R2
    35  	ADDU	R3, R1
    36  
    37  setup:
    38  	AND	$31, R2, R6
    39  	AND	$3, R2, R5
    40  	SUBU	R6, R4, R6	// end pointer for 32-byte chunks
    41  	SUBU	R5, R4, R5	// end pointer for 4-byte chunks
    42  
    43  large:
    44  	BEQ	R1, R6, words
    45  	MOVW	R0, 0(R1)
    46  	MOVW	R0, 4(R1)
    47  	MOVW	R0, 8(R1)
    48  	MOVW	R0, 12(R1)
    49  	MOVW	R0, 16(R1)
    50  	MOVW	R0, 20(R1)
    51  	MOVW	R0, 24(R1)
    52  	MOVW	R0, 28(R1)
    53  	ADDU	$32, R1
    54  	JMP	large
    55  
    56  words:
    57  	BEQ	R1, R5, tail
    58  	MOVW	R0, 0(R1)
    59  	ADDU	$4, R1
    60  	JMP	words
    61  
    62  tail:
    63  	BEQ	R1, R4, ret
    64  	MOVWLO	R0, -1(R4)
    65  
    66  ret:
    67  	RET
    68  
    69  small_zero:
    70  	BEQ	R1, R4, ret
    71  	MOVB	R0, 0(R1)
    72  	ADDU	$1, R1
    73  	JMP	small_zero
    74
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