You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
27 lines
756 B
27 lines
756 B
1 year ago
|
# C runtime, modified from
|
||
|
|
# https://twilco.github.io/riscv-from-scratch/2019/04/27/riscv-from-scratch-2.html#stop--hammertime-runtime
|
||
|
|
|
||
|
|
# in the init section which is "allocatable" and "executable"
|
||
|
|
.section .init, "ax"
|
||
|
|
|
||
|
|
# entry point for the kernel
|
||
|
|
.global _start
|
||
|
|
_start:
|
||
|
|
.cfi_startproc
|
||
|
|
.cfi_undefined ra
|
||
|
|
# initialize the global pointer register
|
||
|
|
.option push
|
||
|
|
.option norelax
|
||
|
|
la gp, __global_pointer$
|
||
|
|
.option pop
|
||
|
|
# initialize the stack pointer and frame pointer registers
|
||
|
|
# FIXME: when putting the stack at the end of RAM with system memory >2G
|
||
|
|
# it fails to link with the error: relocation truncated to fit:
|
||
|
|
# R_RISCV_HI20 against '__stack_top'
|
||
|
|
la sp, __stack_top
|
||
|
|
add s0, sp, zero
|
||
|
|
# jump to main
|
||
|
|
jal zero, main
|
||
|
|
.cfi_endproc
|
||
|
|
|
||
|
|
.end
|