84 lines
1.4 KiB
ArmAsm
84 lines
1.4 KiB
ArmAsm
.global main
|
|
.global isr
|
|
|
|
.section .text.start
|
|
.global _start
|
|
|
|
_start:
|
|
j crt_init
|
|
|
|
.section .text
|
|
.global trap_entry
|
|
trap_entry:
|
|
sw x1, - 1*4(sp)
|
|
sw x5, - 2*4(sp)
|
|
sw x6, - 3*4(sp)
|
|
sw x7, - 4*4(sp)
|
|
sw x10, - 5*4(sp)
|
|
sw x11, - 6*4(sp)
|
|
sw x12, - 7*4(sp)
|
|
sw x13, - 8*4(sp)
|
|
sw x14, - 9*4(sp)
|
|
sw x15, -10*4(sp)
|
|
sw x16, -11*4(sp)
|
|
sw x17, -12*4(sp)
|
|
sw x28, -13*4(sp)
|
|
sw x29, -14*4(sp)
|
|
sw x30, -15*4(sp)
|
|
sw x31, -16*4(sp)
|
|
addi sp,sp,-16*4
|
|
call isr
|
|
lw x1 , 15*4(sp)
|
|
lw x5, 14*4(sp)
|
|
lw x6, 13*4(sp)
|
|
lw x7, 12*4(sp)
|
|
lw x10, 11*4(sp)
|
|
lw x11, 10*4(sp)
|
|
lw x12, 9*4(sp)
|
|
lw x13, 8*4(sp)
|
|
lw x14, 7*4(sp)
|
|
lw x15, 6*4(sp)
|
|
lw x16, 5*4(sp)
|
|
lw x17, 4*4(sp)
|
|
lw x28, 3*4(sp)
|
|
lw x29, 2*4(sp)
|
|
lw x30, 1*4(sp)
|
|
lw x31, 0*4(sp)
|
|
addi sp,sp,16*4
|
|
mret
|
|
|
|
.text
|
|
crt_init:
|
|
la sp, _estack - 4
|
|
la a0, trap_entry
|
|
csrw mtvec, a0
|
|
|
|
bss_init:
|
|
la a0, _sbss
|
|
la a1, _ebss + 4
|
|
bss_loop:
|
|
beq a0,a1,bss_done
|
|
sw zero,0(a0)
|
|
add a0,a0,4
|
|
j bss_loop
|
|
bss_done:
|
|
|
|
/* Load DATA */
|
|
la t0, _etext
|
|
la t1, _srelocate
|
|
la t2, _erelocate + 4
|
|
3:
|
|
lw t3, 0(t0)
|
|
sw t3, 0(t1)
|
|
/* _edata is aligned to 4 bytes. Use word-xfers. */
|
|
addi t0, t0, 4
|
|
addi t1, t1, 4
|
|
bltu t1, t2, 3b
|
|
|
|
li a0, 0x880 //880 enable timer + external interrupt sources (until mstatus.MIE is set, they will never trigger an interrupt)
|
|
csrw mie,a0
|
|
|
|
call main
|
|
infinite_loop:
|
|
j infinite_loop
|