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redcode committed Nov 30, 2024
1 parent f5e519d commit 2204578
Showing 1 changed file with 10 additions and 9 deletions.
19 changes: 10 additions & 9 deletions sources/Z80.c
Original file line number Diff line number Diff line change
Expand Up @@ -2235,10 +2235,11 @@ INSN(xy_xy)

/* MARK: - Instructions: Illegal */

/*----------------------------------------------------------------.
| The CPU ignores illegal opcodes prefixed with EDh. In practice, |
| they are all equivalent to two `nop` instructions (8 T-states). |
'================================================================*/
/*------------------------------------------------------------------------.
| Illegal opcodes prefixed with EDh are ignored by the CPU. Functionally, |
| these instructions are equivalent to two consecutive `nop` instructions |
| and take a total of 8 T-states. |
'========================================================================*/

INSN(ed_illegal)
{
Expand All @@ -2254,11 +2255,11 @@ INSN(ed_illegal)
}


/*-----------------------------------------------------------------------.
| Illegal opcodes with the prefix DDh or FDh cause the CPU to ignore the |
| prefix, i.e., the byte immediately following the prefix is interpreted |
| as the first byte of a new instruction. The prefix takes 4 T-states. |
'=======================================================================*/
/*-------------------------------------------------------------------------.
| Illegal opcodes prefixed with DDh or FDh make the CPU ignore the prefix, |
| As a result, the byte that immediately follows the prefix is treated as |
| the first byte of a new instruction. The prefix takes 4 T-states. |
'=========================================================================*/

INSN(xy_illegal)
{
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