The second example of three is obviously missing the following line:

. subb a,r7 ;subtracting >100 sets cy

I cleaned it up a little and removed an unnecessary label:

. ;{LT vs EQ+GT}:
. clr cy ;trick below eliminates this
. mov a,#100d-1 ;force EQ+GT to set CY
. subb a,r7
. jnc LT ;jump if less than 100
. cjne a,#FFh,GT ;(100d-1)-100d
EQ: ;else value equals 100d
...
GT: ;here if value greater than 100d
...
LT: ;here if value less than 100d
...
.end example

-Jay C. Box