KS57C2308/P2308/C2316/P2316

SAM47 INSTRUCTION SET

 

 

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

EA,HL

;

EA 0C3H + 12H = 0D5H

JPS

XXX

;

Jump to XXX; no skip after ADS.

3.If “ADC A,@HL” is followed by an “ADSA,#im”, the ADC skips on overflow to the instruction immediately after the ADS. An “ADSA,#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

 

;

C "0"

LD

A,#8H

;

A 8H

ADS

A,#6H

;

A 8H + 6H = 0EH

ADC

A,@HL

;

A 0EH + 9H + C(0) = 7H, C "1"

ADS

A,#0AH

;

Skip this instruction because C = "1" after ADC result.

JPS

XXX

 

 

b. 3 + 4 decimal addition (the contents of the address specified by the HL register is 4H):

RCF

 

;

C "0"

 

 

LD

A,#3H

;

A 3H

 

 

ADS

A,#6H

;

A 3H

+ 6H

= 9H

ADC

A,@HL

;

A 9H

+ 4H

+ C(0) = 0DH, C "0"

ADS

A,#0AH

;

No skip. A 0DH + 0AH = 7H

 

 

; (The skip function for “ADSA,#im” is inhibited after an

 

 

; “ADC A,@HL” instruction even if an overflow occurs.)

JPS

XXX

 

 

 

 

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Samsung KS57C2308 manual EA ← 0C3H + 12H = 0D5H