/*
* mpvecdigmuladd(mpdigit *b, int n, mpdigit m, mpdigit *p)
*
* p += b*m
*
* each step looks like:
* hi,lo = m*b[i]
* lo += oldhi + carry
* hi += carry
* p[i] += lo
* oldhi = hi
*
* the registers are:
* b = R3
* n = R4
* m = R5
* p = R6
* i = R7
* hi = R8 - constrained by hardware
* lo = R9 - constrained by hardware
* oldhi = R10
* tmp = R11
*
*/
TEXT mpvecdigmuladd(SB),$0
MOVW n+4(FP),R4
MOVW m+8(FP),R5
MOVW p+12(FP),R6
SUB $4, R3 /* pre decrement for MOVWU's */
SUB $4, R6 /* pre decrement for MOVWU's */
MOVW R0, R10
MOVW R0, XER
MOVW R4, CTR
_muladdloop:
MOVWU 4(R3),R9 /* lo = b[i] */
MOVW 4(R6),R11 /* tmp = p[i] */
MULHWU R9,R5,R8 /* hi = (b[i] * m)>>32 */
MULLW R9,R5,R9 /* lo = b[i] * m */
ADDC R10,R9 /* lo += oldhi */
ADDE R0,R8 /* hi += carry */
ADDC R9,R11 /* tmp += lo */
ADDE R0,R8 /* hi += carry */
MOVWU R11,4(R6) /* p[i] = tmp */
MOVW R8,R10 /* oldhi = hi */
BDNZ _muladdloop
