Difference between revisions of "DEC"

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(Created page with '{{Opcode}} The byte specified by the operand is decremented. == Instructions == DEC B - $05 - 1 Machine Cycle DEC C - $0D - 1 Machine Cycle DEC D - $15 - 1 Machine…')
 
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== Flags ==
 
== Flags ==
  
Z: 1 if result is zero; 0 otherwise
+
Z: 1 if result is zero; 0 otherwise
H: 1 if borrow from bit 4, 0 otherwise
+
H: 1 if borrow from bit 4, 0 otherwise
N: 1
+
N: 1
C: not affected
+
C: not affected

Revision as of 09:28, 25 May 2012

This is an article about the GB-Z80 CPU.

Opcodes:

Arithmetic and logical: ADD - ADD (16-bit) including LD HL,SP+nn - ADC - AND - CP - CPL - DAA - DEC - DEC and INC (16-bit) - INC - SBC - SUB - OR - XOR
Conditional: CALL - JP - JR - RET
Load: LD (8-bit) - LD (16-bit)
Extended Set: BIT - RES - RL - RLC - RR - RRC - SET - SLA - SRA - SRL - SWAP

The byte specified by the operand is decremented.

Instructions

DEC B    - $05 - 1 Machine Cycle
DEC C    - $0D - 1 Machine Cycle
DEC D    - $15 - 1 Machine Cycle
DEC E    - $1D - 1 Machine Cycle
DEC H    - $25 - 1 Machine Cycle
DEC L    - $2D - 1 Machine Cycle
DEC (HL) - $35 - 2 Machine Cycle
DEC A    - $3D - 1 Machine Cycle

Flags

Z: 1 if result is zero; 0 otherwise
H: 1 if borrow from bit 4, 0 otherwise
N: 1
C: not affected