other code for not exceeding max value

[dsouza123]

What code can keep a dword from exceeding some max value
without doing

max dd 31
i dd 0

.if i > max
  mov i, max
.endif

Code Select Expand


with the .if

  mov i, 0
  .repeat
    inc i
    .if i > 31
      mov i, 31
    .endif
    more...code
  .until done == 1

tried without

  mov i, 0
  .repeat
    inc i
    and i, 31
    more...code
  .until done == 1


but after i gets to 31 it goes back to 0
instead of remaining at 31

hoped to get 1,2,...31,31,31,31

[Jimg]

try-

.if i<31
  inc i
.endif

[EduardoS]

you won't get the expected result with and,
and i, 31
is the same as i = i mod 32

in this case to avoid if you can do

Code Select Expand


cmp i, 31
sbb i, 0

or

Code Select Expand


cmp i, 31
cmovc i, 31

or millions others possibilities.

[dsouza123]

Thanks for the replies.

Tested

Code Select Expand


.if i<31
  inc i
.endif

it works

also

Code Select Expand


cmp i, 31
sbb i, 0

it needed a slight tweek and an instruction

Code Select Expand


cmp i, 32
cmc
sbb i, 0


other code that works

Code Select Expand


.data
n31 dd not 31

.code
mov eax, n31
add eax, i
sbb dcnt, 0


After more thinking about the issue, it really is a saturated add with 5 bits.

[EduardoS]

also

Code Select Expand


cmp i, 31
sbb i, 0

it needed a slight tweek and an instruction

Code Select Expand


cmp i, 32
cmc
sbb i, 0


true, my mistake, to avoid the cmc you should put 31 in one register and make cmp reg, i instead of cmp i, 31, the code becomes:

Code Select Expand


mov edx, 31
startloop:
inc i
cmp edx, i
sbb i, 0
...

but a better option is:

Code Select Expand


start loop:
cmp i, 31
adc i, 0
...


[dsouza123]

The last ( cmp i, 31 _ adc i, 0 ) is the best, two instructions, no jumps, flexible max value.