Motorola HC12 - Manual (Page 131)

Assembler Syntax
Source Line
MCUez HC12 Assembler User’s Manual
MOTOROLA Assembler Syntax 131
One very common programming error is to omit the # character. This causes the
assembler to misinterpret the expression as an address rather than explicit data.
Example:
LDAA $60
means load accumulator A with the value stored at address $60 .
7.4.3.3 Direct
The direct addressing mode is used to access operands in the direct page of the
memory (location $0000 to $00FF).
Access to this memory range (also called zero page) is faster and requires less
code than the extended addressing mode (see next example). To speed up the
application, a programmer can place the most commonly accessed data in this
area of memory.
Example:
ORG $50
data: DS.B 1
MyCode: SECTION
Entry:
LDS #$AFE ; init Stack Pointer
LDAA #$01
main: STAA data
BRA main
In this example, the value in register A is stored in the variable data which is
located at address $50 .