diff options
| author | Samuel Holland <[email protected]> | 2024-08-29 13:13:52 -0700 |
|---|---|---|
| committer | Anup Patel <[email protected]> | 2024-09-25 09:46:35 +0530 |
| commit | 7c409091592780284fa99992e225126732f7aae5 (patch) | |
| tree | c8c88cf168f6989fa8b768e9a1780b605ccab112 | |
| parent | 7179e36ce76379e717fe32f2228600cd80366daa (diff) | |
firmware: Simplify FDT header endianness conversion
Reduce the code size by using single-byte loads instead of bit
manipulation. This method also does the right thing on (hypothetical)
big-endian systems.
Signed-off-by: Samuel Holland <[email protected]>
Reviewed-by: Anup Patel <[email protected]>
| -rw-r--r-- | firmware/fw_base.S | 26 |
1 files changed, 5 insertions, 21 deletions
diff --git a/firmware/fw_base.S b/firmware/fw_base.S index b950c0b8..0b58cc42 100644 --- a/firmware/fw_base.S +++ b/firmware/fw_base.S @@ -242,30 +242,14 @@ _scratch_init: beq t1, a1, _fdt_reloc_done /* t0 = source FDT start address */ add t0, a1, zero - /* t2 = source FDT size in big-endian */ -#if __riscv_xlen > 32 - lwu t2, 4(t0) -#else - lw t2, 4(t0) -#endif - /* t3 = bit[15:8] of FDT size */ - add t3, t2, zero - srli t3, t3, 16 - and t3, t3, a4 + /* t2 = source FDT size (convert from big-endian) */ + lbu t2, 7(t0) + lbu t3, 6(t0) + lbu t4, 5(t0) + lbu t5, 4(t0) slli t3, t3, 8 - /* t4 = bit[23:16] of FDT size */ - add t4, t2, zero - srli t4, t4, 8 - and t4, t4, a4 slli t4, t4, 16 - /* t5 = bit[31:24] of FDT size */ - add t5, t2, zero - and t5, t5, a4 slli t5, t5, 24 - /* t2 = bit[7:0] of FDT size */ - srli t2, t2, 24 - and t2, t2, a4 - /* t2 = FDT size in little-endian */ or t2, t2, t3 or t2, t2, t4 or t2, t2, t5 |