diff options
Diffstat (limited to 'libmp/Plan9-mips/mpvecadd.s')
| -rw-r--r-- | libmp/Plan9-mips/mpvecadd.s | 67 |
1 files changed, 67 insertions, 0 deletions
diff --git a/libmp/Plan9-mips/mpvecadd.s b/libmp/Plan9-mips/mpvecadd.s new file mode 100644 index 00000000..8d3e8d63 --- /dev/null +++ b/libmp/Plan9-mips/mpvecadd.s @@ -0,0 +1,67 @@ +#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 + * + * R1 == a (first arg passed in R1) + * R3 == carry + * R4 == alen + * R5 == b + * R6 == blen + * R7 == sum + * R2 == temporary + * 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 + SUBU R6, R4 /* calculate counter for second loop (alen > blen) */ + MOVW R0, R3 + + /* if blen == 0, don't need to add it in */ + BEQ R6,_add1 + + /* sum[0:blen-1],carry = a[0:blen-1] + b[0:blen-1] */ +_addloop1: + MOVW 0(R1), R8 + ADDU $4, R1 + MOVW 0(R5), R9 + ADDU $4, R5 + ADDU R3, R8 + SGTU R3, R8, R3 + ADDU R8, R9 + SGTU R8, R9, R2 + ADDU R2, R3 + MOVW R9, 0(R7) + ADDU $4, R7 + SUBU $1, R6 + BNE R6, _addloop1 + +_add1: + /* if alen == blen, we're done */ + BEQ R4, _addend + + /* sum[blen:alen-1],carry = a[blen:alen-1] + 0 + carry */ +_addloop2: + MOVW 0(R1), R8 + ADDU $4, R1 + ADDU R3, R8 + SGTU R3, R8, R3 + MOVW R8, 0(R7) + ADDU $4, R7 + SUBU $1, R4 + BNE R4, _addloop2 + + /* sum[alen] = carry */ +_addend: + MOVW R3, 0(R7) + RET |