s5u1c33000c Epson Electronics America, Inc., s5u1c33000c Datasheet - Page 180

• Manufacturer Part Number: s5u1c33000c
• Description: Cmos 32-bit Single Chip Microcomputer S5u1c33000c Manual
• Manufacturer: Epson Electronics America, Inc.

CHAPTER 11: ASSEMBLER
11.7 Definition of Sections
In addition to the programs that control the CPU and peripheral circuits, the source file contains permanently
fixed data, such as character generators, which does not require initialization, symbols for the variables stored in
RAM and I/O memory control registers. These data and symbols, which bear different attributes, must finally be
relocated into the corresponding physical memory locations by the linker, for example, programs must be
relocated into the program area in ROM, and fixed data into the data area in ROM. For this reason, the
Assembler is designed in such a way that the object code is classified by attribute into each section.
The following three sections exist:
1. CODE section
2. DATA section
3. BSS section
To allow to specify these sections in assembly source files, the as33 comes provided with pseudo-instructions.
Since the Compiler generates pseudo-instructions, you need not be concerned about sections when programming
the C source.
CODE section
DATA section
BSS section
164
The .code pseudo-instruction defines a CODE section. A statement from this instruction to an instruction
that defines some other section is assumed to be a program code/data, and is an object for the CODE section.
The source file will be regarded as a CODE section by default. Therefore, the part that goes from top of the
file, to another section will be processed as CODE section.
The .data pseudo-instruction defines a DATA section. A statement from this instruction to an instruction
that defines some other section is assumed to be data, and is an object for the DATA section. Therefore,
nothing but the symbols to reference addresses and the pseudo-instructions to define data
(.word, .half, .byte, .ascii, .space), those to define alignment (.align), and comments can be written in this
area. Although data can be written in the CODE section too, if you want the data blocks to be stored
separately from programs after they are linked, data must be written in the DATA section.
The .comm pseudo-instruction and the .lcomm pseudo-instruction are designed to define the symbol and
size of a variables area. When either one of the instructions is described, the symbol will be set in a BSS
section. Although the BSS section basically consists in a RAM area, it can as well be used as a data memory
area, such as I/O memory. Code definition in this area is meaningless in embedded type microcomputers,
such as those of the S1C33 Family. When some other instruction or definition follows the .comm or .lcomm
pseudo-instruction, the section changes to the type defined prior to the BSS section.
Although this section has no actual data as an object, it is required to generate symbol and map information.
Block for programs
Block for the data to be written into ROM
Block that is mapped into RAM, etc.
EPSON
(C COMPILER PACKAGE FOR S1C33 FAMILY) (Ver. 4)
S5U1C33000C MANUAL