diff options
Diffstat (limited to 'tinyusb/hw/bsp/fomu/crt0-vexriscv.S')
-rwxr-xr-x | tinyusb/hw/bsp/fomu/crt0-vexriscv.S | 83 |
1 files changed, 83 insertions, 0 deletions
diff --git a/tinyusb/hw/bsp/fomu/crt0-vexriscv.S b/tinyusb/hw/bsp/fomu/crt0-vexriscv.S new file mode 100755 index 00000000..d80a29e0 --- /dev/null +++ b/tinyusb/hw/bsp/fomu/crt0-vexriscv.S @@ -0,0 +1,83 @@ +.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 |