0
Ball In A Box Productions
; *** Iterate through all combinations of a fixed ; *** number of bits in reverse order bitOdom2 proc STDCALL bitCount:DWORD, highBit:DWORD sub edx,edx ; zero to bit pattern mov eax,bitCount ; number of bits in pattern bts edx,eax ; set the nth bit on dec edx ; number of required bits on next: sub ecx,ecx ; zero a back counter mov ebx,highBit ; number of bits in pattern lp00: inc ecx ; increment the back counter bsr eax,edx ; bit search right je noBits ; no bits left btr edx,eax ; reset the left most bit inc eax ; point to next bit left dec ebx ; reduce the highest bit position cmp ebx,eax ; compare current high to bit pos jc lp00 ; loop if bit outside range lp01: bts edx,eax ; set one bit on in new position inc eax ; next hightest bit position loop lp01 ; dec back count, loop if not zero ; *** odometer values incremented and correct nop ; action to be taken jmp next ; loop and get next bit pattern noBits: ret bitOdom2 endppseudocode
bitCount = number of bits in odometer
highBit = highest bit number
odom = ( 2 ^ highBit ) -1
do
high = highBit
count = 0
do
increment count
index leftmost 1 bit in odom
set indexed bit to 0 in odom
decrement high
increment index
loop while index > high and odom > 0
if odom > 0
do
set the indexed bit on in odom
increment index
decrement count
loop while count > 0
rem action to be taken
end if
loop while odom > 0
highBit = highest bit number
odom = ( 2 ^ highBit ) -1
do
high = highBit
count = 0
do
increment count
index leftmost 1 bit in odom
set indexed bit to 0 in odom
decrement high
increment index
loop while index > high and odom > 0
if odom > 0
do
set the indexed bit on in odom
increment index
decrement count
loop while count > 0
rem action to be taken
end if
loop while odom > 0
More