4 ms·

In the x86 family anyway, it's kinda-sorta 'built in'. It is possible to avoid using the stack -- it's done in interrupt handlers which do not have a stack of t

In the x86 family anyway, it's kinda-sorta 'built in'. It is possible to avoid using the stack -- it's done in interrupt handlers which do not have a stack of their own and must avoid clobbering it -- but most code uses it fairly frequently and there are many auxiliary instructions that push and pop from the stack. In addition to some explicit stack-related instructions like PUSH/POP, PUSHF/POPF, PUSHA/POPA, PUSHAD/POPAD and many others, certain other operations assume you have a valid stack and act on it. For example, the CALL function (used to call a procedure/function) will push a return address to the stack, and RET (used to return to the caller at the end of a procedure/method) will pop the return address to the stack and jump to it. These instructions are fairly essential to the function calling conventions for typical code, enough that it's reasonable to say that the concept of the stack is 'built into' x86 processors. Partly this is because the x86 processor is a beast with an instruction for everything. Other more RISCy architectures tend to not bake in the stack, and instead you use any general-purpose register as a stack pointer and manipulate it manually with regular instructions. http://en.wikipedia.org/wiki/X86_instruction_listings http://en.wikipedia.org/wiki/X86_instruction_listings

joezydeco 13y ago
Lots of smaller microprocessors live by the stack. Aside from the typical JSR/RET stuff with pushing the program counter, you can also do very lightweight programming tricks with the stack pointer. For example, you can pass arguments to an assembly subroutine by putting the data right after the JSR call. The called subroutine pulls the args by manipulating the stack pointer and the return will jump PC after the argument date. You can also use stack pointer to briefly allocate a small amount of memory for scratch inside a routine instead of allocating heap or using globals. This is a big help on small micros where you might get a scratch register or two normally but now you need 4 or 8 bytes for a quick piece of work.

joezydeco 13y ago

Lots of smaller microprocessors live by the stack. Aside from the typical JSR/RET stuff with pushing the program counter, you can also do very lightweight programming tricks with the stack pointer. For example, you can pass arguments to an assembly subroutine by putting the data right after the JSR call. The called subroutine pulls the args by manipulating the stack pointer and the return will jump PC after the argument date. You can also use stack pointer to briefly allocate a small amount of memory for scratch inside a routine instead of allocating heap or using globals. This is a big help on small micros where you might get a scratch register or two normally but now you need 4 or 8 bytes for a quick piece of work.