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<strong>eZ80</strong> <strong>CPU</strong><br />
User Manual<br />
117<br />
RETN<br />
Return from Nonmaskable Interrupt<br />
Operation<br />
Description<br />
PC ← (SP)<br />
ADL Prefix Operation<br />
0 None Pop a 2-byte logical return address using SPS mapped by MBASE into PC.<br />
Keep ADL cleared to 0.<br />
1 None Pop a 3-byte return address using SPL into PC.<br />
Keep ADL set to 1.<br />
0 .S or .L Pop a byte using SPL and load its units bit into ADL.<br />
—If ADL is still cleared to 0, pop a 2-byte logical return address using SPS<br />
mapped by MBASE into PC.<br />
—If ADL is now set to 1, pop a byte from SPL into PC (23-16). Then pop two<br />
bytes from SPS mapped by MBASE into PC (15-0).<br />
1 .S or .L Pop a byte using SPL and load its units bit into ADL.<br />
—If ADL is now cleared to 0, pop a 2-byte logical address from SPL into PC.<br />
—If ADL is still set to 1, pop a 3-byte address from SPL into PC.<br />
Condition Bits Affected<br />
None<br />
Mnemonic Operands ADL Mode Cycles Op Codes<br />
RETN — 0/1 * ED, 45<br />
RETN.S — 0 * 40, ED, 45<br />
RETN.S — 1 * 52, ED, 45<br />
RETN.L — 0 * 49, ED, 45<br />
RETN.L — 1 * 5B, ED, 45<br />
UM007701-1100
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