Merge #214
214: faster zeroing of .bss r=JOE1994 a=JOE1994
This PR updates the code for zeroing the .bss section.
The updated version uses `core::ptr::write_bytes()` which invokes a single **memset**,
compared to the current code which initializes one byte at a time.
The updated version would initialize the .bss section faster than the current version.
Thank you for reviewing this PR :) :bowing_man:
Co-authored-by: JOE1994 <joseph942010@gmail.com>
diff --git a/core/src/entry_point/mod.rs b/core/src/entry_point/mod.rs
index 2ab2351..850c213 100644
--- a/core/src/entry_point/mod.rs
+++ b/core/src/entry_point/mod.rs
@@ -104,10 +104,8 @@
);
// Zero .bss (specified by the linker script).
- let bss_end = layout_header.bss_start + layout_header.bss_size; // 1 past the end of .bss
- for i in layout_header.bss_start..bss_end {
- core::ptr::write(i as *mut u8, 0);
- }
+ let bss_start = layout_header.bss_start as *mut u8;
+ core::ptr::write_bytes(bss_start, 0u8, layout_header.bss_size);
// TODO: Wait for rustc to have working ROPI-RWPI relocation support, then
// implement dynamic relocations here. At the moment, rustc does not have
