DP8344 datasheet(144/184 Pages) NSC

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60 Reference Section (Continued)

LCALL

Conditional Long Call

Syntax

LCALL

Rs p s nn

Affected Flags

None

Description

If the bit in position p of register Rs is equal to the bit s then

push the Program Counter the ALU flags the Global Inter-

rupt Enable bit GIE

and the current register bank selec-

tions onto the internal Address Stack Following the push

transfer control to the instruction at the absolute memory

address nn The operand Rs may specify any active CPU

sponds to the LSB of Rs and 7 corresponds to the MSB of

Rs The absolute value nn is 16 bits long (range 0 to 64k)

therefore all of instruction memory can be addressed

Example

Call the ‘‘LoadXmit’’ subroutine when the Transmitter FIFO

Empty flag

TFE

of the Network Command Flag register

NCF is ‘‘1’’

EXX

select main A alt B

LCALL NCF71 LoadXmit

If TFE e1 call

Instruction Format

1000111

Opcode

T-states

(2 a 2)

Bus Timing

Figure 6-3

Operation

If Rs p e s then

GIE

ALU flags

x Address Stack

xPC

End if

LCALL

Unconditional Long Call

Syntax

LCALL

absolute

Affected Flags

None

Description

Pushes the Program Counter the ALU flags the Global In-

terrupt Enable bit GIE and the current register bank selec-

tions onto the internal Address Stack then unconditionally

transfers control to the instruction at the absolute memory

address nn The value of nn is 16 bits long (range 0 to

64k) therefore all of instruction memory can be addressed

Example

Transfer control to the subroutine ‘‘Senditall’’ which could

be located anywhere in instruction memory

LCALL

Senditall

Instruction Format

1100111010000000

Opcode

T-states

(2 a 2)

Bus Timing

Figure 6-3

Operation

GIE

ALU flags

x Address Stack

xPC

144

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