DECR

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Instruction NameDecrement Register
MnemonicDECR
CP1610 Clock Cycles6
InterruptibleYes
Opcode Range$0010-$0017
Input FlagsNone
Output FlagsSign Flag, Zero Flag

The Decrement Register (DECR) instruction decrements the specified register by one (1) and sets or clears the Sign Flag and Zero Flag according to the results.

   0000:0000:0001:0rrr
where: rrr indicates the target register such that: rrr == 000 indicates register R0 rrr == 001 indicates register R1 rrr == 010 indicates register R2 rrr == 011 indicates register R3 rrr == 100 indicates register R4 rrr == 101 indicates register R5 rrr == 110 indicates register R6 rrr == 111 indicates register R7