Zilog Z16F2810 - Manual (Page 131)

UM018809-0611 LD Instruction
ZNEO
®
CPU Core
User Manual
115
LD
Definition
Load
Syntax
LD dst, src
Operation
dst

src
Description
The contents of the source operand are loaded into the destination operand. The contents of the
source operand are unaffected. The default data size is 32 bits. Byte (8-bit) or Word (16-bit) data
size can usually be selected by adding a .B or .W, suffix, respectively, to the LD mnemonic.
When a 32-bit value is loaded into an 8- or 16-bit memory location, the value is truncated to fit
the destination size.
When an 8- or 16-bit value is loaded into a larger location, it must be extended to fill all the des-
tination bits. A “U” in the mnemonic suffix selects zero (unsigned) extension. An “S” in the mne-
monic suffix selects signed extension. An immediate source operand is always sign extended.
A “--” prefix in a register-indirect operand indicates that the address register is decremented
before the operation. A “++” suffix indicates that the address register is incremented after the
operation. Register predecrement and postincrement do not affect flags. See EXT for instructions
to load register values with extension.
See LEA for synonyms to LD opcodes that are useful for loading an effective address.
See PUSH and POP for instructions that store and retrieve stack data.