[CA850] Startup Module

In the default startup routine, a stack area is allocated to a .bss section.
What setting should be made to locate a stack area at specified addresses?

To locate a stack area at specified addresses, the stack area must be allocated to a section other than .bss.

This can be done by specifying the most significant address of the section + 1 (must be arranged at a 4-byte boundary) to the sp register (r3 register) in the startup routine, and specifying the address of the section with a link directive.

Example:

To create a stack area of a 0x200-byte section from address 0x3ffee00 in the section name of .stack


[Allocating stack area in assembler source]

	.set STACKSIZE, 0x200
	.section ".stack", bss 
	.lcomm	__stack, STACKSIZE, 4

[sp register setting in startup routine]

	mov	#__stack+STACKSIZE, sp

[Specifying by link directive]

STACK    : !LOAD ?RW V0x3ffee00 {
        .stack          = $NOBITS       ?AW .stack;
};