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Z80 instruction set

Reference

Instruction	Opcode	Time	S	Z	X	H	Y	P	N	C	Effect
adc a,R	10001rrr	4	+	+	+	+	+	V	0	+	a += R + cf
adc a,N	11001110 nnnnnnnn	7	+	+	+	+	+	V	0	+	a += N + cf
adc a,(hl)	10001110	7	+	+	+	+	+	V	0	+	a += (hl) + cf
adc a,(ix+D)	11011101 10001110 dddddddd	19	+	+	+	+	+	V	0	+	a += (ix+D) + cf
adc a,(iy+D)	11111101 10001110 dddddddd	19	+	+	+	+	+	V	0	+	a += (iy+D) + cf
adc hl,Q	11101101 01qq1010	15	+	+	+	+	+	V	0	+	hl += Q + cf
add a,R	10000rrr	4	+	+	+	+	+	V	0	+	a += R
add a,N	11000110 nnnnnnnn	7	+	+	+	+	+	V	0	+	a += N
add a,(hl)	10000110	7	+	+	+	+	+	V	0	+	a += (hl)
add a,(ix+D)	11011101 10000110 dddddddd	19	+	+	+	+	+	V	0	+	a += (ix+D)
add a,(iy+D)	11111101 10000110 dddddddd	19	+	+	+	+	+	V	0	+	a += (iy+D)
add hl,Q	00qq1001	11	-	-	+	+	+	-	0	+	hl += Q + cf
add ix,Q	11011101 00qq1001	15	-	-	+	+	+	-	0	+	ix += Q + cf
add iy,Q	11111101 00qq1001	15	-	-	+	+	+	-	0	+	iy += Q + cf
call A	11001101 alalalal ahahahah	17	-	-	-	-	-	-	-	-	sp -= 2, (sp) := pc, pc := A
ccf	00111111	4	-	-	A	X	A	-	0	X	hf := cf, cf := ~cf
ld R1,R2	01rrrsss	4	-	-	-	-	-	-	-	-	R1 := R2
pop P	11pp0001	10	-	-	-	-	-	-	-	-	P := (sp), sp += 2
push P	11pp0101	11	-	-	-	-	-	-	-	-	sp -= 2, (sp) := P
ret	11001001	10	-	-	-	-	-	-	-	-	pc := (sp), sp += 2

Legend

Notation	Meaning	Respective opcode bits
A	16-bit address	alalalal ahahahah
D	8-bit signed relative offset	dddddddd
N	8-bit immediate	nnnnnnnn
P	16-bit register pair: bc, de, hl, af	pp = 00, 01, 10, 11
Q	16-bit register: bc, de, hl, sp	qq = 00, 01, 10, 11
R	8-bit general purpose register: a, b, c, d, e, h, l	rrr (or sss) = 111, 000, 001, 010, 011, 100, 101

Flags

• - = no change
• + = change by definition:
  • S = sign, bit 7 of the result byte (accumulator or high byte for 16-bit operations)
  • Z = zero, set if the result is zero (8 or 16-bit value)
  • X = undocumented, bit 5 of the result byte
  • H = half-carry, the carry of the low nibble of the result byte
  • Y = undocumented, bit 3 of the result byte
  • P = parity (set if the result byte has an even number of bits set) or overflow (set when crossing the boundary of the signed range); always specified
  • N = negative, set if the previous operation was a subtraction; always specified
  • C = carry, the theoretical bit 8 of the result byte
• 0 = always reset
• 1 = always set
• X = change described under Effect
• P = parity (only for the parity flag)
• V = overflow (only for the parity flag)
• A = OR with the respective bit of the accumulator