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CHAPTER 4: ASSEMBLER
74 EPSON S5U1C63000A MANUAL
(S1C63 FAMILY ASSEMBLER PACKAGE)
4.7.7 Location Defining Pseudo-Instructions (.org, .align)
The absolute addressing pseudo-instructions (.align and .org) work to specify absolute location of a
section in different precision such as 2
n
words alignment level and complete absolute address level.
.org pseudo-instruction
Instruction format
.org <Address>
<Address>:
Absolute address specification
• Only decimal, binary and hexadecimal numbers can be described.
• The addresses that can be specified are from 0 to 65,535 (0xffff).
• One or more spaces or tabs are necessary between the instruction and the address.
Sample description:
.code
.org 0x0100
Function
Specifies an absolute address location of a CODE, DATA or BSS section in an assembly source file. The
section with the .org pseudo-instruction is taken as an absolute section.
Precautions
• If an overlap occurs as the result of specifying absolute locations with the .org pseudo-instruction, an
error will result.
Examples:
.bss
.org 0x00
.comm RAM0 4 ... RAM secured area (0x00–0x03)
.org 0x01
.comm RAM1 4 ... Error (because the area of 0x01–0x03 is overlapped)
• When the .org pseudo-instruction appears in a section, a new absolute section starts at that point. The
section type does not change. The .org pseudo-instruction keeps its effect only in that section until the
next section definer (.code, .data or .bss) or the next location definer (.org or .align) appears.
Example:
:
.code ... The latest relocatable section definition.
:
.org 0x100 ... Starts new absolute CODE section from address 0x100.
:
.bss ... This section is relocatable not affected by the ".org" pseudo-instruction.
:
.code ... This section is also relocatable not affected by the ".org" pseudo-instruction.
:
• If the .org pseudo-instruction is defined immediately after a section definer (.code, .data or .bss), the
section definer does not start a new section. But .org starts a new section with the attribute of the
section definer.
Example:
.code ... This does not start a new CODE section.
.org 0x100 ... This starts an absolute CODE section.
: