Bit Manipulation Group
- Gunther Strube
Owned by Gunther Strube
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Mnemonic Symbolic Flags (bit 7-0) Instruction Number Number of Number of Comments
operation S Z . H . V N C opcode of bytes M cycles T states
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BIT b,r Fz <- NOT rb X ? X 1 X X 0 * 11 001 011 (CBh) 2 2 8 r:
01 <b> <r> 000 C
001 B
BIT b,(HL) Fz <- NOT (HL)b X ? X 1 X X 0 * 11 001 011 (CBh) 2 3 12 010 E
01 <b> 110 011 D
100 L
BIT b,(IX+d) Fz <- NOT (IX+d)b X ? X 1 X X 0 * 11 011 101 (DDh) 4 5 20 101 H
BIT b,(IY+d) Fz <- NOT (IY+d)b X ? X 1 X X 0 * 11 111 101 (FDh) 4 5 20 111 A
11 001 011 (CBh)
-- <d> ---
01 <b> 110 b:
000 0
001 1
SET b,r rb <- 1 * * X * X * * * 11 001 011 (CBh) 2 2 8 010 2
11 <b> <r> 011 3
100 4
SET b,(HL) (HL)b <- 1 * * X * X * * * 11 001 011 (CBh) 2 4 15 101 5
11 <b> 110 110 6
111 7
SET b,(IX+d) (IX+d)b <- 1 * * X * X * * * 11 011 101 (DDh) 4 6 23
SET b,(IY+d) (IY+d)b <- 1 * * X * X * * * 11 111 101 (FDh) 4 6 23
11 001 011 (CBh)
-- <d> ---
11 <b> 110
RES b,r rb <- 0 * * X * X * * * 11 001 011 (CBh) 2 2 8
10 <b> <r>
RES b,(HL) (HL)b <- 0 * * X * X * * * 11 001 011 (CBh) 2 4 15
10 <b> 110
RES b,(IX+d) (IX+d)b <- 0 * * X * X * * * 11 011 101 (DDh) 4 6 23
RES b,(IY+d) (IY+d)b <- 0 * * X * X * * * 11 111 101 (FDh) 4 6 23
11 001 011 (CBh)
-- <d> ---
10 <b> 110
Please note:
The bit to be tested by the BIT instruction is first inverted before copied to Fz, ie. Fz = 1 if the corresponding bit is zero. Fz = 0 if the corresponding bit is 1.