github.com/dorkamotorka/go/src@v0.0.0-20230614113921-187095f0e316/crypto/internal/bigmod/nat_ppc64x.s (about)

     1  // Copyright 2013 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 !purego && (ppc64 || ppc64le)
     6  
     7  #include "textflag.h"
     8  
     9  // func addMulVVW1024(z, x *uint, y uint) (c uint)
    10  TEXT ·addMulVVW1024(SB), $0-32
    11  	MOVD	$16, R22 // R22 = z_len
    12  	JMP		addMulVVWx(SB)
    13  
    14  // func addMulVVW1536(z, x *uint, y uint) (c uint)
    15  TEXT ·addMulVVW1536(SB), $0-32
    16  	MOVD	$24, R22 // R22 = z_len
    17  	JMP		addMulVVWx(SB)
    18  
    19  // func addMulVVW2048(z, x *uint, y uint) (c uint)
    20  TEXT ·addMulVVW2048(SB), $0-32
    21  	MOVD	$32, R22 // R22 = z_len
    22  	JMP		addMulVVWx(SB)
    23  
    24  TEXT addMulVVWx(SB), NOFRAME|NOSPLIT, $0
    25  	MOVD z+0(FP), R10	// R10 = z[]
    26  	MOVD x+8(FP), R8	// R8 = x[]
    27  	MOVD y+16(FP), R9	// R9 = y
    28  
    29  	MOVD R0, R3		// R3 will be the index register
    30  	CMP  R0, R22
    31  	MOVD R0, R4		// R4 = c = 0
    32  	MOVD R22, CTR		// Initialize loop counter
    33  	BEQ  done
    34  	PCALIGN $16
    35  
    36  loop:
    37  	MOVD  (R8)(R3), R20	// Load x[i]
    38  	MOVD  (R10)(R3), R21	// Load z[i]
    39  	MULLD  R9, R20, R6	// R6 = Low-order(x[i]*y)
    40  	MULHDU R9, R20, R7	// R7 = High-order(x[i]*y)
    41  	ADDC   R21, R6		// R6 = z0
    42  	ADDZE  R7		// R7 = z1
    43  	ADDC   R4, R6		// R6 = z0 + c + 0
    44  	ADDZE  R7, R4           // c += z1
    45  	MOVD   R6, (R10)(R3)	// Store z[i]
    46  	ADD    $8, R3
    47  	BC  16, 0, loop		// bdnz
    48  
    49  done:
    50  	MOVD R4, c+24(FP)
    51  	RET