S3C84E5/C84E9/P84E9

INSTRUCTION SET

 

 

LDB — Load Bit

LDB

dst,src.b

LDB

dst.b,src

Operation:

dst(0)

src(b)

 

or

 

 

dst(b)

src(0)

 

The specified bit of the source is loaded into bit zero (LSB) of the destination, or bit zero of the

 

source is loaded into the specified bit of the destination. No other bits of the destination are affected.

 

The source is unaffected.

Flags:

No flags are affected.

Format:

 

 

 

 

 

 

 

 

 

 

 

Bytes

Cycles

Opcode

Addr Mode

 

 

 

 

 

 

(Hex)

dst

src

 

 

 

 

 

 

 

 

 

 

opc

dst b 0

src

3

6

47

r0

Rb

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

opc

src b 1

dst

3

6

47

Rb

r0

 

 

 

 

 

 

 

 

 

NOTE: In the second byte of the instruction format, the destination (or the source) address is four bits, the bit address "b" is three bits, and the LSB address value is one bit in length.

Examples: Given: R0 = 06H and general register 00H = 05H:

LDB

R0,00H.2

R0

=

07H, register 00H

=

05H

LDB

00H.0,R0

R0

=

06H, register 00H

=

04H

In the first example, the destination working register R0 contains the value 06H and the source general register 00H the value 05H. The statement "LD R0,00H.2" loads the bit two value of the 00H register into bit zero of the R0 register, leaving the value 07H in the register R0.

In the second example, 00H is the destination register. The statement "LD 00H.0,R0" loads bit zero of the register R0 to the specified bit (bit zero) of the destination register, leaving 04H in the general register 00H.

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Image 178
Samsung S3C84E5 user manual LDB Load Bit, Ldb, Dst Examples Given R0 = 06H and general register 00H = 05H