Samsung KS57C2308 Manual page 155

KS57C2308/P2308/C2316/P2316
SBC
— Subtract With Carry
SBC (Continued)
Examples: 3. If SBC A,@HL is followed by an ADS A,#im, the SBC skips on "no borrow" to the instruction
immediately after the ADS. An "ADS A,#im" instruction immediately after the "SBC A,@HL"
instruction does not skip even if an overflow occurs. This function is useful for decimal
adjustment operations.
a. 8 – 6 decimal addition (the contents of the address specified by the HL register is 6H):
RCF
LD
SBC
ADS
JPS
b. 3 – 4 decimal addition (the contents of the address specified by the HL register is 4H):
RCF
LD
SBC
ADS
JPS
A,#8H
A,@HL
A,#0AH
XXX
A,#3H
A,@HL
A,#0AH
XXX
; C "0"
; A 8H
; A 8H – 6H – C(0) = 2H, C
; Skip this instruction because no borrow after SBC result
; C "0"
; A 3H
; A 3H – 4H – C(0) = 0FH, C
; No skip. A 0FH + 0AH = 9H
; (The skip function of "ADS A,#im" is inhibited after a
; "SBC A,@HL" instruction even if an overflow occurs.)
SAM47 INSTRUCTION SET
"0"
"1"
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