Beannaich at 12:30, 25 May 2012

2012-05-25T12:30:58Z

Beannaich: Wrote up an initial description of the LD op-codes.

2012-05-25T11:10:38Z

Wrote up an initial description of the LD op-codes.

New page

{{Opcode}}
== Load (8-bit) ==

This instructions move the contents of a register or memory location into a destination register or memory location. These commands do not affect any CPU flags, and they require 1 machine cycle to complete (Plus 1 machine cycle if (HL) is used as a source or destination).

The op-codes for this group are encoded as follows:

01dddsss
| || |
| |+-+- Source Register
+-+---- Destination Register

Where 'd' and 's' are values from the following:

000: B
001: C
010: D
011: E
100: H
101: L
110: (HL)
111: A

Example: LD B,L would be encoded as 01000101 represented in hexadecimal as $45.

'''NOTE: LD (HL),(HL) does not exist, that instruction ($76) executes the HALT instruction.'''

== 8-bit Immediate Load ==

These instructions allow a constant value to be loaded from the program into a register of choice. These commands do not affect any CPU flags, and they require 2 machine cycles to complete.

00ddd110 nnnnnnnn
| | | |
| | +------+- Operand
+-+------------- Destination Register

Where 'n' is the 8-bit immediate, and 'd' is a value from the following:

000: B
001: C
010: D
011: E
100: H
101: L
110: (HL)
111: A

Example: LD H, $A6 would be encoded as 00100110 10100110 represented in hexadecimal as $26 $A6

@@ Line 1: / Line 1: @@
 {{Opcode}}
-== Load (8-bit) ==
+== 8-bit Register Load ==
 This instructions move the contents of a register or memory location into a destination register or memory location. These commands do not affect any CPU flags, and they require 1 machine cycle to complete (Plus 1 machine cycle if (HL) is used as a source or destination).

LD (8-bit) - Revision history

Beannaich at 12:30, 25 May 2012

Beannaich: Wrote up an initial description of the LD op-codes.