ADC = Addition with Carry (8-Bits)
| Hex | Mnemonic | Cycles |
|---|---|---|
| 08 | ADC A, A | 8 |
| 09 | ADC A, B | 8 |
| 0A nn | ADC A, #nn | 8 |
| 0B | ADC A, [HL] | 8 |
| 0C nn | ADC A, [N+#nn] | 12 |
| 0D nn nn | ADC A, [#nnnn] | 16 |
| 0E | ADC A, [X] | 8 |
| 0F | ADC A, [Y] | 8 |
| CE 08 ss | ADC A, [X+#ss] | 16 |
| CE 09 ss | ADC A, [Y+#ss] | 16 |
| CE 0A | ADC A, [X+L] | 16 |
| CE 0B | ADC A, [Y+L] | 16 |
| CE 0C | ADC [HL], A | 16 |
| CE 0D nn | ADC [HL], #nn | 20 |
| CE 0E | ADC [HL], [X] | 20 |
| CE 0F | ADC [HL], [Y] | 20 |
Execute
#nn = Immediate unsigned 8-Bits
#ss = Immediate signed 8-Bits
A = Register A
B = Register B
[N+#nn] = Memory: (I shl 16) or (N shl 8) or #nn
[HL] = Memory: (I shl 16) or HL
[X] = Memory: (XI shl 16) or X
[Y] = Memory: (YI shl 16) or Y
[#nnnn] = Memory: (I shl 16) or #nnnn
[X+#ss] = Memory: (XI shl 16) or (X + #ss)
[Y+#ss] = Memory: (YI shl 16) or (Y + #ss)
[X+L] = Memory: (XI shl 16) or (X + signed(L))
[Y+L] = Memory: (YI shl 16) or (Y + signed(L))
; ADC Ds, Sc
;
; Ds = Destination
; Sc = Source
; (If flags BCD=0 and NIBBLE=0)
Ds = Ds + Sc + Carry
;------------------------------------------------
; (If flags BCD=0 and NIBBLE=1)
Ds & 0x0F = (Ds & 0x0F) + (Sc & 0x0F) + Carry
;------------------------------------------------
; (If flags BCD=1 and NIBBLE=0)
IF (((Ds & 15) + (Sc & 15) + Carry) >= 10) THEN
Ds = Ds + Sc + Carry + 6
ELSE
Ds = Ds + Sc + Carry
ENDIF
IF (Ds >= 0xA0) Ds = Ds + 0x60
;------------------------------------------------
; (If flags BCD=1 and NIBBLE=1)
IF (((Ds & 15) + (Sc & 15) + Carry) >= 10) THEN
Ds & 0x0F = (Ds & 0x0F) + (Sc & 0x0F) + Carry + 6
ELSE
Ds & 0x0F = (Ds & 0x0F) + (Sc & 0x0F) + Carry
ENDIF
Description
8-Bits Source and Carry adds to the 8-Bits Destination.
Conditions
If flags BCD=0 and NIBBLE=0
Zero: Set when result is 0
Carry: Set when result is >= 256
Overflow: Set when result overflow 8-bits signed range (< -128 OR > 127)
Sign: Set when bit 7 of the result is 1
If flags BCD=0 and NIBBLE=1
Zero: Set when result is 0
Carry: Set when result is >= 16
Overflow: Set when result overflow 4-bits signed range (< -16 OR > 15)
Sign: Set when bit 3 of the result is 1
If flags BCD=1 and NIBBLE=0
Zero: Set when result is 0
Carry: Set when result is >= 100
Overflow: Always Reset
Sign: Always Reset
If flags BCD=1 and NIBBLE=1
Zero: Set when result is 0
Carry: Set when result is >= 10
Overflow: Always Reset
Sign: Always Reset
Examples
; A = 0x55
; F = (Carry=1)
ADC A, $80
; A = 0xD6 (0x55 + 0x80 + 0x01 = 0x(0)D6)
; F = (Zero=0):(Carry=0):(Overflow=1):(Sign=1)
; B = 0x31
; A = 0xCF
; F = (Carry=0)
ADC A, B
; B = 0x31
; A = 0x00 (0xCF + 0x31 + 0x00 = 0x(1)00)
; F = (Zero=1):(Carry=1):(Overflow=0):(Sign=0)
; [HL] = 0xDE
; A = 0xCF
; F = (Carry=0)
ADC A, [HL]
; [HL] = 0xDE
; A = 0xAD (0xCF + 0xDE + 0x00 = 0x(1)AD)
; F = (Zero=0):(Carry=1):(Overflow=0):(Sign=1)
; ( BCD = 1, NIBBLE = 0 )
; A = 0x09
; F = (Carry=1)
ADC A, $01
; A = 0x11 (09 + 01 + 01 = 11)
; F = (Zero=0):(Carry=0):(Overflow=0):(Sign=0)
; ( BCD = 0, NIBBLE = 1 )
; A = 0x3F (Note, in "nibble mode" the high nibble is always discarded)
; F = (Carry=1)
ADC A, $01
; A = 0x01 (0xF + 0x1 + 0x1 = 0x(1)1)
; F = (Zero=1):(Carry=1):(Overflow=0):(Sign=0)