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REP: Difference between revisions

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'''REP''' (Reset Status Bits) is a [[65c816]] instruction that clears bits in the [[status register]] that correspond to set bits in the operand.
'''REP''' (Reset Status Bits) is a [[65c816]] instruction that clears bits in the [[status register]] that correspond to set bits in the operand.


REP appears to be the only way to clear the m and x flags other than [[PLP]] and [[RTI]].
REP is the only way to clear the m and x flags directly (but [[PLP]] and [[RTI]] may too.)<sup>[1]</sup>


==== Syntax ====
==== Syntax ====
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* [[Derailment]]
* [[Derailment]]


=== External Links ===
=== References ===
* [[Eyes & Lichty]] page 489, on REP: https://archive.org/details/0893037893ProgrammingThe65816/page/n515
# [[Eyes & Lichty]] page 489, on REP: https://archive.org/details/0893037893ProgrammingThe65816/page/n515
* [[Labiak]] page 173 on REP: https://archive.org/details/Programming_the_65816/page/n183
# [[Labiak]] page 173 on REP: https://archive.org/details/Programming_the_65816/page/n183
* snes9x implementation of REP: https://github.com/snes9xgit/snes9x/blob/master/cpuops.cpp#L3145
# snes9x implementation of REP: https://github.com/snes9xgit/snes9x/blob/master/cpuops.cpp#L3145
* undisbeliever on REP: https://undisbeliever.net/snesdev/65816-opcodes.html#rep-reset-status-bits
# undisbeliever on REP: https://undisbeliever.net/snesdev/65816-opcodes.html#rep-reset-status-bits


[[Category:ASM]]
[[Category:ASM]]

Revision as of 03:47, 8 July 2024

Basic Info
Addressing Mode Opcode Length Speed
Immediate C2 2 bytes 3 cycles
Flags Affected
N V M X D I Z C
emulation mode . .
native mode

REP (Reset Status Bits) is a 65c816 instruction that clears bits in the status register that correspond to set bits in the operand.

REP is the only way to clear the m and x flags directly (but PLP and RTI may too.)[1]

Syntax

REP #nvmxdizc

See Also

References

  1. Eyes & Lichty page 489, on REP: https://archive.org/details/0893037893ProgrammingThe65816/page/n515
  2. Labiak page 173 on REP: https://archive.org/details/Programming_the_65816/page/n183
  3. snes9x implementation of REP: https://github.com/snes9xgit/snes9x/blob/master/cpuops.cpp#L3145
  4. undisbeliever on REP: https://undisbeliever.net/snesdev/65816-opcodes.html#rep-reset-status-bits
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