Samsung KS57C2308 Manual page 101

KS57C2308/P2308/C2316/P2316
ADS
— Add And Skip On Overflow
ADS (Continued)
Examples: 2. If the extended accumulator contains the value 0C3H, register pair HL the value 12H, and
the carry flag = "0":
ADS
JPS
3. If "ADC A,@HL" is followed by an "ADS A,#im", the ADC skips on overflow to the instruction
immediately after the ADS. An "ADS A,#im" instruction immediately after the "ADC A,@HL"
does not skip even if overflow occurs. This function is useful for decimal adjustment
operations.
a. 8 + 9 decimal addition (the contents of the address specified by the HL register is 9H):
RCF
LD
ADS
ADC
ADS
JPS
b. 3 + 4 decimal addition (the contents of the address specified by the HL register is 4H):
RCF
LD
ADS
ADC
ADS
JPS
EA,HL
XXX
A,#8H
A,#6H
A,@HL
A,#0AH
XXX
A,#3H
A,#6H
A,@HL
A,#0AH
XXX
; EA 0C3H + 12H = 0D5H
; Jump to XXX; no skip after ADS.
; C "0"
; A 8H
; A 8H + 6H = 0EH
; A 0EH + 9H + C(0) = 7H, C
; Skip this instruction because C = "1" after ADC result.
; C "0"
; A 3H
; A 3H + 6H = 9H
; A 9H + 4H + C(0) = 0DH, C
; No skip. A 0DH + 0AH = 7H
; (The skip function for "ADS A,#im" is inhibited after an
; "ADC A,@HL" instruction even if an overflow occurs.)
SAM47 INSTRUCTION SET
"1"
"0"
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