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Diffstat (limited to 'scripts/romload/start.S')
| -rw-r--r-- | scripts/romload/start.S | 86 |
1 files changed, 86 insertions, 0 deletions
diff --git a/scripts/romload/start.S b/scripts/romload/start.S new file mode 100644 index 0000000..73e4ba3 --- /dev/null +++ b/scripts/romload/start.S @@ -0,0 +1,86 @@ +.section .text +.global _start +.global _pvstart +.global _data +.global _data_lma + +_pvstart: +/* zero-initialize all registers */ +addi x1, zero, 0 +addi x2, zero, 0 +addi x3, zero, 0 +addi x4, zero, 0 +addi x5, zero, 0 +addi x6, zero, 0 +addi x7, zero, 0 +addi x8, zero, 0 +addi x9, zero, 0 +addi x10, zero, 0 +addi x11, zero, 0 +addi x12, zero, 0 +addi x13, zero, 0 +addi x14, zero, 0 +addi x15, zero, 0 +addi x16, zero, 0 +addi x17, zero, 0 +addi x18, zero, 0 +addi x19, zero, 0 +addi x20, zero, 0 +addi x21, zero, 0 +addi x22, zero, 0 +addi x23, zero, 0 +addi x24, zero, 0 +addi x25, zero, 0 +addi x26, zero, 0 +addi x27, zero, 0 +addi x28, zero, 0 +addi x29, zero, 0 +addi x30, zero, 0 +addi x31, zero, 0 + +/* set stack pointer */ + +lui sp, %hi(4*1024*1024) +addi sp, sp, %lo(4*1024*1024) +/* +lui sp, %hi(0x100000) +addi sp, sp, %lo(0x100000) +*/ +/* push zeros on the stack for argc and argv */ +/* (stack is aligned to 16 bytes in riscv calling convention) */ +addi sp,sp,-16 +sw zero,0(sp) +sw zero,4(sp) +sw zero,8(sp) +sw zero,12(sp) + +/* + // Load data section + la a0, _data_lma + la a1, _data + la a2, _edata + bgeu a1, a2, 2f +1: + lw t0, (a0) + sw t0, (a1) + addi a0, a0, 4 + addi a1, a1, 4 + bltu a1, a2, 1b +2: + + // Clear bss section + la a0, _bss_start + la a1, _bss_end + bgeu a0, a1, 2f +1: + sw zero, (a0) + addi a0, a0, 4 + bltu a0, a1, 1b +2: +*/ + + +/* jump to libc init */ +/*j _ftext + */ +j _start |