PIC18 cheatsheet
ADDWFADDWFCANDWFCLRFCOMFCPFSEQCPFSGTCPFSLTDECFDECFSZDCFSNZINCFINCFSZINFSNZIORWFMOVFMOVFFMOVWFMULWFNEGFRLCFRLNCFRRCFRRNCFSETFSUBFWBSUBWFSUBWFBSWAPFTSTFSZXORWF
BCFBSFBTFSCBTFSSBTG
BCBNBNCBNNBNOVBNZBOVBRABZCALLCLRWDTDAWGOTONOPPOPPUSHRCALLRESETRETFIERETLWRETURNSLEEP
ADDLWANDLWIORLWLFSRMOVLBMOVLWMULLWRETLWSUBLWXORLW
TBLRD*TBLRD*+TBLRD*-TBLRD+*TBLWT*TBLWT*+TBLWT*-TBLWT+*

DAW

Detailed reference for the DAW instruction in PIC18 ISA.

Description

Adjust the contents of WREG after a BCD addition or subtraction, converting the result to a valid Binary‑Coded‑Decimal (BCD) value.

  • Since the operand is implicit, the syntax contains no address or options.
  • The instruction examines the lower nibble, and if it is greater than 9, adds 6 to correct it. It then examines the upper nibble (after the lower‑nibble adjustment); if it is greater than 9 or the B flag is set, it adds 0x60. The carry flag is updated accordingly.
  • Flag updates: The Z, C, and DC bits are set based on the result.

Examples

; After successfull ADDWF, WREG harbours BCD result needing adjustment
DAW ; adjust WREG to BCD format
; After SUBWF, WREG contains BCD difference requiring correction
DAW ; adjust the subtraction result in WREG
; When WREG holds a correctly‑formatted BCD value already
DAW ; no change, but flags updated
; Preloading WREG with a literal and then adjusting
MOVLW 0x09
DAW ; literal is already BCD, no adjustment needed
; Following an addition that set carry, WREG is adjusted and carry cleared
ADDWF 0x12, 1, 0
DAW ; adjust resulting BCD and update carry