diff options
Diffstat (limited to 'libmp/Plan9-power/mpvecadd.s')
| -rw-r--r-- | libmp/Plan9-power/mpvecadd.s | 61 |
1 files changed, 61 insertions, 0 deletions
diff --git a/libmp/Plan9-power/mpvecadd.s b/libmp/Plan9-power/mpvecadd.s new file mode 100644 index 00000000..abbfe53d --- /dev/null +++ b/libmp/Plan9-power/mpvecadd.s @@ -0,0 +1,61 @@ +#define BDNZ BC 16,0, +#define BDNE BC 0,2, + +/* + * mpvecadd(mpdigit *a, int alen, mpdigit *b, int blen, mpdigit *sum) + * + * sum[0:alen] = a[0:alen-1] + b[0:blen-1] + * + * prereq: alen >= blen, sum has room for alen+1 digits + * + * R3 == a (first arg passed in R3) + * R4 == alen + * R5 == b + * R6 == blen + * R7 == sum + * R8 == temporary + * R9 == temporary + */ +TEXT mpvecadd(SB),$-4 + + MOVW alen+4(FP), R4 + MOVW b+8(FP), R5 + MOVW blen+12(FP), R6 + MOVW sum+16(FP), R7 + SUB R6, R4 /* calculate counter for second loop (alen > blen) */ + SUB $4, R3 /* pre decrement for MOVWU's */ + SUB $4, R5 /* pre decrement for MOVWU's */ + SUB $4, R7 /* pre decrement for MOVWU's */ + MOVW R0, XER /* zero carry going in */ + + /* if blen == 0, don't need to add it in */ + CMP R0, R6 + BEQ _add1 + + /* sum[0:blen-1],carry = a[0:blen-1] + b[0:blen-1] */ + MOVW R6, CTR +_addloop1: + MOVWU 4(R3), R8 + MOVWU 4(R5), R9 + ADDE R8, R9 + MOVWU R9, 4(R7) + BDNZ _addloop1 + +_add1: + /* if alen == blen, we're done */ + CMP R0, R4 + BEQ _addend + + /* sum[blen:alen-1],carry = a[blen:alen-1] + 0 + carry */ + MOVW R4, CTR +_addloop2: + MOVWU 4(R3), R8 + ADDE R0, R8 + MOVWU R8, 4(R7) + BDNZ _addloop2 + + /* sum[alen] = carry */ +_addend: + ADDE R0, R0, R8 + MOVW R8, 4(R7) + RETURN |