diff options
Diffstat (limited to 'libc/bcc/__ldivmod.c')
| -rw-r--r-- | libc/bcc/__ldivmod.c | 40 |
1 files changed, 20 insertions, 20 deletions
diff --git a/libc/bcc/__ldivmod.c b/libc/bcc/__ldivmod.c index 596d022..359c692 100644 --- a/libc/bcc/__ldivmod.c +++ b/libc/bcc/__ldivmod.c @@ -8,35 +8,35 @@ .text .even -| ldivmod.s - 32 over 32 to 32 bit division and remainder for 8086 +! ldivmod.s - 32 over 32 to 32 bit division and remainder for 8086 -| ldivmod( dividend bx:ax, divisor di:cx ) [ signed quot di:cx, rem bx:ax ] -| ludivmod( dividend bx:ax, divisor di:cx ) [ unsigned quot di:cx, rem bx:ax ] +! ldivmod( dividend bx:ax, divisor di:cx ) [ signed quot di:cx, rem bx:ax ] +! ludivmod( dividend bx:ax, divisor di:cx ) [ unsigned quot di:cx, rem bx:ax ] -| dx is not preserved +! dx is not preserved -| NB negatives are handled correctly, unlike by the processor -| divison by zero does not trap +! NB negatives are handled correctly, unlike by the processor +! divison by zero does not trap -| let dividend = a, divisor = b, quotient = q, remainder = r -| a = b * q + r mod 2^32 -| where: +! let dividend = a, divisor = b, quotient = q, remainder = r +! a = b * q + r mod 2^32 +! where: -| if b = 0, q = 0 and r = a +! if b = 0, q = 0 and r = a -| otherwise, q and r are uniquely determined by the requirements: -| r has the same sign as b and absolute value smaller than that of b, i.e. -| if b > 0, then 0 <= r < b -| if b < 0, then 0 >= r > b -| (the absoulute value and its comparison depend on signed/unsigned) +! otherwise, q and r are uniquely determined by the requirements: +! r has the same sign as b and absolute value smaller than that of b, i.e. +! if b > 0, then 0 <= r < b +! if b < 0, then 0 >= r > b +! (the absoulute value and its comparison depend on signed/unsigned) -| the rule for the sign of r means that the quotient is truncated towards -| negative infinity in the usual case of a positive divisor +! the rule for the sign of r means that the quotient is truncated towards +! negative infinity in the usual case of a positive divisor -| if the divisor is negative, the division is done by negating a and b, -| doing the division, then negating q and r +! if the divisor is negative, the division is done by negating a and b, +! doing the division, then negating q and r .globl ldivmod @@ -105,7 +105,7 @@ divlarge: cmp dx,ax ja zdivu -| rotate w (= b) to greatest dyadic multiple of b <= r +! rotate w (= b) to greatest dyadic multiple of b <= r loop1: shl dx,*1 ! w = 2*w |