NEC PD754144 - Manual (Page 273)

CHAPTER 11 INSTRUCTION SET
273 User’s Manual U10676EJ3V0UM
11.4.6 Increment/decrement instructions
INCS reg
Function: reg ← reg+1; Skip if reg = 0
Increments the contents of register reg (X, A, H, L, D, E, B, or C). If reg = 0 as a result, the next instruction is
skipped.
INCS rp1
Function: rp1 ← rp1+1; Skip if rp1 = 00H
Increments the contents of register pair rp1 (HL, DE, or BC). If rp1 = 00H as a result, the next instruction is skipped.
INCS @HL
Function: (HL) ← (HL)+1; Skip if (HL) = 0
Increments the contents of the data memory addressed by pair register HL. If the contents of the data memory
become 0 as a result, the next instruction is skipped.
INCS mem
Function: (mem) ← (mem) + 1; Skip if (mem) = 0, mem = D 7-0 : 00H to FFH
Increments the contents of the data memory addressed by 8-bit immediate data mem. If the contents of the data
memory become 0 as a result, the next instruction is skipped.
DECS reg
Function: reg ← reg–1; Skip if reg = FH
Decrements the contents of register reg (X, A, H, L, D, E, B, or C). If reg = FH as a result, the next instruction
is skipped.
DECS rp’
Function: rp’ ← rp’–1; Skip if rp’ = FFH
Decrements the contents of register pair rp' (XA, HL, DE, BC, XA', HL', DE', or BC'). If rp’ = FFH as a result, the
next instruction is skipped.