Intel IA-32 - Manual (Page 407)

Vol. 3A 9-33
PROCESSOR MANAGEMENT AND INITIALIZATION
9.10.3 MAIN.ASM Source Code
The file MAIN.ASM shown in Example 9-2 defines the data and stack segments for this appli-
cation and can be substituted with the main module task written in a high-level language that is
invoked by the IRET instruction executed by STARTUP.ASM.
Example 9-2. MAIN.ASM
NAME main_module
data SEGMENT RW
dw 1000 dup(?)
DATA ENDS
stack stackseg 800
CODE SEGMENT ER use32 PUBLIC
main_start:
nop
nop
nop
CODE ENDS
END main_start, ds:data, ss:stack
9.10.4 Supporting Files
The batch file shown in Example 9-3 can be used to assemble the source code files
STARTUP.ASM and MAIN.ASM and build the final application.
Example 9-3. Batch File to Assemble and Build the Application
ASM386 STARTUP.ASM
ASM386 MAIN.ASM
BLD386 STARTUP.OBJ, MAIN.OBJ buildfile(EPROM.BLD) bootstrap(STARTUP)
Bootload
BLD386 performs several operations in this example:
•
It allocates physical memory location to segments and tables.
•
It generates tables using the build file and the input files.
•
It links object files and resolves references.
•
It generates a boot-loadable file to be programmed into the EPROM.
Example 9-4 shows the build file used as an input to BLD386 to perform the above functions.