W = value
addlw 255 - Hi addlw (Hi - Lo) + 1
Carry is set if W is in range Lo - Hi
It works for all values of Hi and Lo although it is not optimal for 255 and 0. It even works for ranges that wrap around 255 back to 0. For instance, if you set Lo to 240 and Hi to 15, it will match 0..15 and also 240..255. And it works for signed numbers. You can set Lo to -3 and Hi to 5 to match -3..+5.
The only requirement is that your assembler must truncate literals to eight bits. If not, you can still use it by masking the literals yourself:
addlw (255 - Hi) & 0ffh addlw ((Hi - Lo) + 1) & 0ffh
For example:
Lower = 50 Upper = 60 addlw 255 - Hi equates to addlw 195 addlw (Hi - Lo) + 1 equates to addlw 11 W = 50 ; lower limit addlw 195 ; w = 245 addlw 11 ; w = 0, C = 1, result = OK W = 55 ; in range addlw 195 ; w = 250 addlw 11 ; w = 5, C = 1, result = OK W = 60 ; upper limit addlw 195 ; w = 255 addlw 11 ; w = 11, C = 1, result = OK W = 49 ; under minimum addlw 195 ; w = 244 addlw 11 ; w = 255, C = 0, result = Not OK W = 61 ; over maximum addlw 195 ; w = 0 addlw 11 ; w = 11, C = 0, result = Not OK