Motorola HC12 用户手册

User’s Manual

MCUez HC12 Assembler

110

Sections

MOTOROLA

In the previous example, two bytes of storage are allocated starting at address

$A00.

 Symbol

cst1

 will be allocated at address

$A00

 and

cst2

 will be

allocated at address

$A01

. All subsequent instructions or data allocation

directives will be located in the absolute section until another section is
specified using the ORG or SECTION directive.

When using absolute sections, the user is responsible for ensuring that no
overlap exists between the different absolute sections defined in the application.
In the previous example, the programmer should ensure that the size of the
section starting at address

$A00

is not bigger than

$200

bytes; otherwise, the

sections starting at

$A00

 and

$C00

 will overlap.

When object files are generated, applications containing only absolute sections
must be linked. In that case, there should be no overlap between address ranges
from the absolute sections defined in the assembly file and address ranges
defined in the linker parameter file.

The PRM (parameter) file used to link the previous example, is defined in

LINK test.abs

/* Name of the executable file generated. */

NAMES

  test.o

/* Name of object files in the application. */

END

SEGMENTS

/* READ_ONLY memory area. There should be no overlap between this

   memory area and the absolute sections defined in the assembly

   source file. */

  MY_ROM  = READ_ONLY  0x1000 TO 0x1FFF;

/* READ_WRITE memory area. There should be no overlap between this

   memory area and the absolute sections defined in the assembly

   source file. */

  MY_RAM  = READ_WRITE 0x2000 TO 0x2FFF;

END

PLACEMENT

/* Relocatable variable sections are allocated in MY_RAM. */

  .data    INTO MY_RAM;

/* Relocatable code and constant sections are allocated in MY_ROM. */

  .text    INTO MY_ROM;

END

INIT entry

/*  Application entry point */

VECTOR ADDRESS 0xFFFE entry /* Initialization of the reset vector */