Intel 80C188XL User Manual

Page 349

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INSTRUCTION SET DESCRIPTIONS

C-26

LDS

Load Pointer Using DS:

LDS

dest, src

Transfers a 32-bit pointer variable from
the source operand, which must be a
memory operand, to the destination
operand and register DS. The offset
word of the pointer is transferred to the
destination operand, which may be
any 16-bit general register. The
segment word of the pointer is
transferred to register DS.

Instruction Operands:

LDS reg16, mem32

(dest)

(EA)

(DS)

(EA + 2)

AF –
CF –
DF –
IF –
OF –
PF –
SF –
TF –
ZF –

LEA

Load Effective Address:

LEA dest, src

Transfers the offset of the source
operand (rather than its value) to the
destination operand.

Instruction Operands:

LEA reg16, mem16

(dest)

EA

AF –
CF –
DF –
IF –
OF –
PF –
SF –
TF –
ZF –

LEAVE

Leave:

LEAVE

Reverses the action of the most recent
ENTER instruction. Collapses the last
stack frame created. First, LEAVE
copies the current BP to the stack
pointer releasing the stack space
allocated to the current procedure.
Second, LEAVE pops the old value of
BP from the stack, to return to the
calling procedure's stack frame. A
return (RET) instruction will remove
arguments stacked by the calling
procedure for use by the called
procedure.

Instruction Operands:

none

(SP)

(BP)

(BP)

((SP) + 1:(SP))

(SP)

(SP) + 2

AF –
CF –
DF –
IF –
OF –
PF –
SF –
TF –
ZF –

Table C-4. Instruction Set (Continued)

Name

Description

Operation

Flags

Affected

NOTE:

The three symbols used in the Flags Affected column are defined as follows:
– the contents of the flag remain unchanged after the instruction is executed
? the contents of the flag is undefined after the instruction is executed

ü

the flag is updated after the instruction is executed

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