View source for Z80 wait instructions

Z80 instruction set that don't change registers value (except for F register):
{| class="wikitable"
! Inst. !! T-S !! Bytes !! Flag modification
|-
| <tt>NOP</tt>                    ||  5 || 1 || None
|-
| <tt>CP (HL)</tt>                ||  8 || 1 || C, S, and Z flags modified by definition. P/V detects overflow.
|-
| <tt>NOP<br/>NOP</tt>            || 10 || 2 || None
|-
| <tt>SCF<br/>RET NC</tt>         || 11 || 2 || Carry flag set, H and N cleared, rest are preserved.
|-
| <tt>JR $+2</tt>                 || 13 || 2 || None
|-
| <tt>BIT 0,(HL)</tt>             || 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.
|-
| <tt>NOP<br/>NOP<br/>NOP</tt>    || 15 || 3 || None
|-
| <tt>CP (HL)<BR/>CP (HL)</tt>    || 16 || 2 || C, S, and Z flags modified by definition. P/V detects overflow.
|-
| <tt>SCF<br/>RET NC<br/>RET NC</tt> || 17 || 3 || Carry flag set, H and N cleared, rest are preserved.
|-
| <tt>NOP<br/>JR $+2</tt>         || 18 || 3 || None
|-
| <tt>NOP<br/>BIT 0,(HL)</tt>     || 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.
|-
| <tt>NOP<br/>NOP<br/>NOP<br/>NOP</tt> || 20 || 4 || None
|-
| <tt>CP (IY+0)</tt>              || 21 || 3 || C, S, and Z flags modified by definition. P/V detects overflow.
|-
| <tt>CP (HL)<br/>BIT 0,(HL)</tt> || 22 || 3 || C, S, and Z flags modified by definition. P/V detects overflow.<br/>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.
|-
| <tt>PUSH AF<br/>POP AF</tt>     || 23 || 2 || None
|-
| <tt>CP (HL)<BR/>CP (HL)<BR/>CP (HL)</tt> || 24 || 3 || C, S, and Z flags modified by definition. P/V detects overflow.
|- style="background-color:lightgray;"
| <tt>INC (HL)<br/>DEC (HL)</tt>  || 24 || 2 || Preserves C flag, N flag is reset, P/V detects overflow and rest are modified by definition.<br/>C flag preserved, P/V detects overflow and rest modified by definition.<br/>⚠️ Not interrupt safe
|-
| <tt>NOP<br/>NOP<br/>NOP<br/>NOP<br/>NOP</tt> || 25 || 5 || None
|-
| <tt>JR $+2<br/>JR $+2</tt>      || 26 || 4 || None
|-
| <tt>NOP<br/>CP (HL)<br/>BIT 0,(HL)</tt> || 27 || 4 || C, S, and Z flags modified by definition. P/V detects overflow.<br/>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.
|-
| <tt>NOP<br/>PUSH AF<br/>POP AF</tt> || 28 || 3 || None
|-
| <tt>CP (IY+0)<br/>CP (HL)</tt>  || 29 || 4 || C, S, and Z flags modified by definition. P/V detects overflow.
|- style="background-color:lightgray;"
| <tt>NOP<br/>INC (HL)<br/>DEC (HL)</tt>  || 29 || 3 || Preserves C flag, N flag is reset, P/V detects overflow and rest are modified by definition.<br/>C flag preserved, P/V detects overflow and rest modified by definition.<br/>⚠️ Not interrupt safe
|-
| <tt>BIT 0,(HL)<br/>CP (HL)<br/>CP (HL)</tt> || 30 || 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.<br/>C, S, and Z flags modified by definition. P/V detects overflow.
|}