Difference between revisions of "Z80 wait instructions"

Revision as of 23:27, 2 March 2024

Z80 instruction set that don't change registers value (except for F and R registers):

Inst.	TS	Bytes	Flag modification
`NOP`	5	1	None
`CP (HL)`	8	1	C, S, and Z flags modified by definition. P/V detects overflow.
`NOP NOP`	10	2	None
`LD R,A`	11	2	C is preserved, H and N are reset, and alters Z and S. P/V is set if interrupts are enabled, reset otherwise.
`NOP CP (HL)`	13	2	C, S, and Z flags modified by definition. P/V detects overflow.
`BIT 0,(HL)`	14	2	Opposite of the bit #0 is written into the Z flag. C is preserved, N is reset, H is set, and S and P/V are undefined.
`NOP NOP NOP`	15	3	None
`CP (HL) CP (HL)`	16	2	C, S, and Z flags modified by definition. P/V detects overflow.
`NOP NOP CP (HL)`	18	3	C, S, and Z flags modified by definition. P/V detects overflow.
`NOP BIT 0,(HL)`	19	3	Opposite of the bit #0 is written into the Z flag. C is preserved, N is reset, H is set, and S and P/V are undefined.
`NOP NOP NOP NOP`	20	4	None
`CP (IY+0)`	21	3	C, S, and Z flags modified by definition. P/V detects overflow.
`BIT 0,(IY+0)`	22	4	Opposite of the bit #0 is written into the Z flag. C is preserved, N is reset, H is set, and S and P/V are undefined.
`CP (HL) CP (HL) CP (HL)`	24	3	C, S, and Z flags modified by definition. P/V detects overflow.
`NOP NOP NOP NOP NOP`	25	5	None
`NOP CP (IY+0)`	26	4	C, S, and Z flags modified by definition. P/V detects overflow.
`NOP BIT 0,(IY+0)`	27	5	Opposite of the bit #0 is written into the Z flag. C is preserved, N is reset, H is set, and S and P/V are undefined.

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-Z80 instruction set that don't change registers value (except for F register):
+Z80 instruction set that don't change registers value (except for F and R registers):
 {| class="wikitable"
 ! Inst. !! TS !! Bytes !! Flag modification