This page introduces the main function/routine in RISC-V programs.
When writing a RISC-V program, and not just a function, the
starting or entry point for executing the code is the main function.
The main
label behaves similar to any other
function in the .text section; there is just some behind the scenes work
to tell the assembler to "Start here". An example of the main function in
RISC-V:
# Needs to be in the text section as it is code.
.text
main:
# Program code.
# It is also a good idea to explicitly exit from the program,
# so it doesn't just fall off and stop executing.
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In the majority of programming assignments, the main appears in a
common.s file and should not be included in the solution. The grading
system uses a different common.s code that might call the function in the
solution several times. Therefore, it is important that the function in the
solution has a proper return statement -- it cannot simply terminate the
program when it is done.