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#define	BDNZ	BC	16,0,
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#define	BDNE	BC	0,2,
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/*
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 *	mpvecadd(mpdigit *a, int alen, mpdigit *b, int blen, mpdigit *sum)
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 *
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 *		sum[0:alen] = a[0:alen-1] + b[0:blen-1]
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 *
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 *	prereq: alen >= blen, sum has room for alen+1 digits
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 *
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 *		R3 == a	(first arg passed in R3)
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 *		R4 == alen
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 *		R5 == b
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 *		R6 == blen
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 *		R7 == sum
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 *		R8 == temporary
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 *		R9 == temporary
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 */
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TEXT	mpvecadd(SB),$-4
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	MOVW	alen+4(FP), R4
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	MOVW	b+8(FP), R5
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	MOVW	blen+12(FP), R6
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	MOVW	sum+16(FP), R7
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	SUB	R6, R4		/* calculate counter for second loop (alen > blen) */
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	SUB	$4, R3		/* pre decrement for MOVWU's */
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	SUB	$4, R5		/* pre decrement for MOVWU's */
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	SUB	$4, R7		/* pre decrement for MOVWU's */
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	MOVW	R0, XER		/* zero carry going in */
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	/* if blen == 0, don't need to add it in */
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	CMP	R0, R6
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	BEQ	_add1
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	/* sum[0:blen-1],carry = a[0:blen-1] + b[0:blen-1] */
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	MOVW	R6, CTR
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_addloop1:
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	MOVWU	4(R3), R8
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	MOVWU	4(R5), R9
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	ADDE	R8, R9
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	MOVWU	R9, 4(R7)
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	BDNZ	_addloop1
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_add1:
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	/* if alen == blen, we're done */
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	CMP	R0, R4
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	BEQ	_addend
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	/* sum[blen:alen-1],carry = a[blen:alen-1] + 0 + carry */
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	MOVW	R4, CTR
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_addloop2:
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	MOVWU	4(R3), R8
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	ADDE	R0, R8
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	MOVWU	R8, 4(R7)
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	BDNZ	_addloop2
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	/* sum[alen] = carry */
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_addend:
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	ADDE	R0, R0, R8
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	MOVW	R8, 4(R7)
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	RETURN