diff options
Diffstat (limited to 'src/libmp/port/mpdiv.c')
| -rw-r--r-- | src/libmp/port/mpdiv.c | 38 |
1 files changed, 19 insertions, 19 deletions
diff --git a/src/libmp/port/mpdiv.c b/src/libmp/port/mpdiv.c index 92aee03f..90ab4ba5 100644 --- a/src/libmp/port/mpdiv.c +++ b/src/libmp/port/mpdiv.c @@ -2,9 +2,9 @@ #include <mp.h> #include "dat.h" -// division ala knuth, seminumerical algorithms, pp 237-238 -// the numbers are stored backwards to what knuth expects so j -// counts down rather than up. +/* division ala knuth, seminumerical algorithms, pp 237-238 */ +/* the numbers are stored backwards to what knuth expects so j */ +/* counts down rather than up. */ void mpdiv(mpint *dividend, mpint *divisor, mpint *quotient, mpint *remainder) @@ -13,11 +13,11 @@ mpdiv(mpint *dividend, mpint *divisor, mpint *quotient, mpint *remainder) mpdigit qd, *up, *vp, *qp; mpint *u, *v, *t; - // divide bv zero + /* divide bv zero */ if(divisor->top == 0) abort(); - // quick check + /* quick check */ if(mpmagcmp(dividend, divisor) < 0){ if(remainder != nil) mpassign(dividend, remainder); @@ -26,8 +26,8 @@ mpdiv(mpint *dividend, mpint *divisor, mpint *quotient, mpint *remainder) return; } - // D1: shift until divisor, v, has hi bit set (needed to make trial - // divisor accurate) + /* D1: shift until divisor, v, has hi bit set (needed to make trial */ + /* divisor accurate) */ qd = divisor->p[divisor->top-1]; for(s = 0; (qd & mpdighi) == 0; s++) qd <<= 1; @@ -44,13 +44,13 @@ mpdiv(mpint *dividend, mpint *divisor, mpint *quotient, mpint *remainder) vp = v->p+v->top-1; vn = v->top; - // D1a: make sure high digit of dividend is less than high digit of divisor + /* D1a: make sure high digit of dividend is less than high digit of divisor */ if(*up >= *vp){ *++up = 0; u->top++; } - // storage for multiplies + /* storage for multiplies */ t = mpnew(4*Dbits); qp = nil; @@ -60,15 +60,15 @@ mpdiv(mpint *dividend, mpint *divisor, mpint *quotient, mpint *remainder) qp = quotient->p+quotient->top-1; } - // D2, D7: loop on length of dividend + /* D2, D7: loop on length of dividend */ for(j = u->top; j > vn; j--){ - // D3: calculate trial divisor + /* D3: calculate trial divisor */ mpdigdiv(up-1, *vp, &qd); - // D3a: rule out trial divisors 2 greater than real divisor + /* D3a: rule out trial divisors 2 greater than real divisor */ if(vn > 1) for(;;){ - memset(t->p, 0, 3*Dbytes); // mpvecdigmuladd adds to what's there + memset(t->p, 0, 3*Dbytes); /* mpvecdigmuladd adds to what's there */ mpvecdigmuladd(vp-1, 2, qd, t->p); if(mpveccmp(t->p, 3, up-2, 3) > 0) qd--; @@ -76,21 +76,21 @@ mpdiv(mpint *dividend, mpint *divisor, mpint *quotient, mpint *remainder) break; } - // D4: u -= v*qd << j*Dbits + /* D4: u -= v*qd << j*Dbits */ sign = mpvecdigmulsub(v->p, vn, qd, up-vn); if(sign < 0){ - // D6: trial divisor was too high, add back borrowed - // value and decrease divisor + /* D6: trial divisor was too high, add back borrowed */ + /* value and decrease divisor */ mpvecadd(up-vn, vn+1, v->p, vn, up-vn); qd--; } - // D5: save quotient digit + /* D5: save quotient digit */ if(qp != nil) *qp-- = qd; - // push top of u down one + /* push top of u down one */ u->top--; *up-- = 0; } @@ -101,7 +101,7 @@ mpdiv(mpint *dividend, mpint *divisor, mpint *quotient, mpint *remainder) } if(remainder != nil){ - mpright(u, s, remainder); // u is the remainder shifted + mpright(u, s, remainder); /* u is the remainder shifted */ remainder->sign = dividend->sign; } |