11 Dec
2005
11 Dec
'05
9:58 a.m.
On Sun, 11 Dec 2005, Dave Dunfield wrote:
After looking at what I posted in my previous
response, I realized that I
could do the adjustments in single instructions by alternating ACI and
SBI instructions - took a little bit of head scratching to work through the
carries and come up with the right numbers, however this little sequence
will do it in only 8 instructions (plus the ANI 15 which isn't really part of
the algorithm if you need it):
ANI $0F
ADI $F6
ACI $0A
SBI $09
SBI $F5
ACI $F6
ACI $0A
SBI $09
SBI $C5
These are 9 instructions taking 18 bytes.
How about this:
SET R1,#$F0
LBI R2,#$F9
SLE R1,R2
SUB R1,#$39
Four instructions, eight bytes, EBCDIC character as output! Now guess what
machine this is for. Hint: the machine has no flags and no stack.
Christian