77 lines
1.3 KiB
ArmAsm
77 lines
1.3 KiB
ArmAsm
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// Carry arithmetic, rotates, unsigned/signed division and bit tests: the
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// scalar families GOROOT's big-number and crypto kernels use. Every result
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// is folded back so no instruction is dead.
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#include "textflag.h"
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// func carry(a, b uint64) uint64
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TEXT ·carry(SB), NOSPLIT, $0-24
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MOVQ a+0(FP), AX
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MOVQ b+8(FP), BX
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ADDQ BX, AX
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ADCQ $0, AX
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MOVQ BX, CX
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SBBQ $1, CX
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ADCL BX, AX
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ADCB AL, BL
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ADCW $7, CX
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MOVQ AX, ret+16(FP)
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RET
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// func borrow(a, b uint64) uint64
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TEXT ·borrow(SB), NOSPLIT, $0-24
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MOVQ a+0(FP), AX
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MOVQ b+8(FP), BX
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SUBQ BX, AX
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SBBQ $0, AX
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SBBQ BX, CX
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MOVQ AX, ret+16(FP)
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RET
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// func rot(x uint64, n uint32) uint64
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TEXT ·rot(SB), NOSPLIT, $0-24
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MOVQ x+0(FP), AX
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MOVL n+8(FP), CX
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ROLQ CL, AX
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RORQ $7, AX
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ROLL $1, AX
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RORL CL, AX
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RCLQ $1, AX
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RCRQ CL, AX
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ROLW $3, AX
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SALQ $2, AX
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SALB $1, AX
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MOVQ AX, ret+8(FP)
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RET
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// func muldiv(a, b uint64) uint64
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TEXT ·muldiv(SB), NOSPLIT, $0-24
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MOVQ a+0(FP), AX
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MOVQ b+8(FP), BX
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MULQ BX
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MULQ (BX)
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MOVL (BX), CX
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MULL CX
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DIVQ BX
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IDIVQ BX
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MOVL a+0(FP), AX
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DIVL CX
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IDIVL CX
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MOVQ AX, ret+16(FP)
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RET
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// func bitfield(w *uint64) uint64
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TEXT ·bitfield(SB), NOSPLIT, $0-16
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MOVQ (DI), AX
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MOVQ (DI), CX
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BTQ AX, CX
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BTQ $3, (DI)
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BTL AX, CX
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BTW $1, CX
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BTSQ $5, AX
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BTRQ AX, CX
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BTCQ $7, (DI)
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SETCS AL
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MOVQ AX, ret+8(FP)
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RET
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