copare gprs

wejos

Member

• Aug 8, 2009

• #1

guys is there a way i could compare two GPRs? the "AND" command drive me crazy can't make it to work since i don't know what to do next. i'm lost.

i tried something like:

A equ 0x0C

movlw 0x61 ;t in ascii
andlw 0x74 ;a in ascii
movwf A



since W was 0x61, the value of A would be 0x60 or

01100001 ----61
01110100 ----74
01100000 ----60

if W was 0x74, the value of A would be 0x74 also or

01110100 ----74
01110100 ----74
01110100 ----74


what i want to happen is compare two GPR, if both are the same, then i can set portA, 0x00 to high.

 

Last edited: Aug 8, 2009

gaspode42

Member

• Aug 8, 2009

• #2

This may be the case however you have the incorrect instruction -
try ANDLW not ADDLW. You could also XOR the two values and then check the result (should be zero).

 

Last edited: Aug 8, 2009

wejos

Member

• Aug 8, 2009

• #3

gaspode42 said:

This may be the case however you have the incorrect instruction -
try ANDLW not ADDLW.

Click to expand...

ty gaspode. i'll edit. i was referring to andlw

 

gaspode42

Member

• Aug 8, 2009

• #4

I was editing while you posted, did you get the XOR idea?

 

Nigel Goodwin

Super Moderator

Most Helpful Member

• Aug 8, 2009

• #5

If you check on the PICList there's an entire section about doing comparisons.

 

wejos

Member

• Aug 8, 2009

• #6

not yet gaspode i'll google about XOR. thank you gaspode and nigel. i'll look for the instruction set of my pic AGAIN lols.

 

wejos

Member

• Aug 8, 2009

• #7

thank you again guys

 

gaspode42

Member

• Aug 8, 2009

• #8

You may find this helpful

 

Attachments

• MPASM_Quick_Ref_Card_30400g.pdf

  139.6 KB · Views: 242

wejos

Member

• Aug 8, 2009

• #9

thank you gaspode very helpful reference

"A lie gets halfway around the world before the truth has a chance to get its pants on"

lols

 

wejos

Member

• Aug 8, 2009

• #10

guys again thank you it worked. gaspode ty for suggesting xor. nigel for your tut, learned a lot from you.