The BSD string functions take a word path only when both pointers are
aligned, and a byte path otherwise. A pair at the same offset from a
boundary takes the byte path even though copying or comparing a few leading
bytes aligns both at once, since aligning one aligns the other.
Add MISALIGNED(), which asks whether two pointers disagree about where a
boundary falls, and walk an agreeing pair up to the boundary before the
existing path selection. MISALIGNED4() does the same for the 4-byte path,
so a pair that is 4-byte but not 8-byte aligned reaches the wide path
instead of the middle one. No existing line changes: the walk is a new step
ahead of the current decisions. A pair at differing offsets still takes the
byte path, since no single boundary serves both.
Measured on an EIC7700 EVB (EIC7700X, RV64GC, 1.4GHz) with the BSD string
functions selected and the RISC-V assembly ones disabled, using the
benchmark in apps#3706, medians of 3 runs in MB/s at its largest size:
equal offset aligned
memcpy 414 -> 4148 10.0x 4214 -> 4208
memcmp 41 -> 361 8.8x 362 -> 360
strncmp 28 -> 202 7.4x 207 -> 207
strcmp 42 -> 273 6.5x 278 -> 276
strncpy 377 -> 1676 4.5x 1824 -> 1748
stpncpy 376 -> 1654 4.4x 1843 -> 1724
stpcpy 551 -> 1833 3.3x 1970 -> 1939
memccpy 650 -> 2012 3.1x 2478 -> 2016
strcpy 636 -> 1837 2.9x 1678 -> 1965
Cases the walk never runs for move in both directions by up to a third, the
largest being memccpy at differing offsets, 648 -> 414. Their code is
unchanged, so that is code placement rather than an effect of the change.
The change is architecture independent but has only been measured on
RV64GC. Word size, alignment cost and byte loop codegen all differ
elsewhere, so the balance wants measuring on other architectures.
Assisted-by: Claude:claude-opus-5
Signed-off-by: Justin Hammond <justin@dynam.ac>
libc_data_t is 8 bytes wide, so a buffer which is 4-byte but not
8-byte aligned falls back to the byte at a time loop. Add a 32-bit
middle path so such buffers still handle four bytes per iteration.
* Add DETECTNULL32/DETECTCHAR32, UNALIGNED4/UNALIGNED4_X,
LITTLEBLOCKSIZE4/BIGBLOCKSIZE4 and TOO_SMALL4 to libs/libc/libc.h.
* Take the new path in memccpy, memcmp, memcpy, memset, stpcpy,
stpncpy, strcmp, strcpy, strncmp and strncpy when both pointers are
4-byte aligned but the 8-byte path can't be used.
Assisted-by: Claude:claude-opus-5
Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>
Most hardware accesses the memory through a 64-bit bus, so handle the
data in 64-bit chunks instead of "long" chunks which are only 32-bit
wide on the 32-bit platforms.
* Add the libc_data_t type (unsigned long long) and move the shared
UNALIGNED/UNALIGNED_X/ALIGNED, LITTLEBLOCKSIZE, TOO_SMALL and
DETECTNULL helpers from the individual C files to libs/libc/libc.h.
* Convert all lib_bsd*.c implementations to the new type and macros,
which also drops the duplicated LONG_MAX conditionals.
Assisted-by: Claude:claude-opus-5
Signed-off-by: anjiahao <anjiahao@xiaomi.com>
Add assembly-optimized implementations for 14 string/memory functions
using word-at-a-time techniques (DETECTNULL, broadcast+XOR) and
XLEN-adaptive macros for both RV32 and RV64:
- memmove: direction check + forward tail to memcpy, reverse path
with 16xSZREG unroll and shift-merge for misaligned src.
- memcmp: word-granularity compare when both pointers share alignment,
bytewise fallback for mismatched pointers.
- memchr: broadcast target byte, XOR with each word, DETECTNULL to
find matches. Counter-based bounds (no pointer overflow).
- strlen: DETECTNULL word loop, constants loaded from .srodata.
- strnlen: strlen with counter-based length limit.
- strcpy/strncpy: word loop with DETECTNULL, zero-fill remainder
for strncpy. strncpy reuses strcpy via #define USE_AS_STRNCPY.
- stpcpy/stpncpy: reuse strcpy/strncpy via #define USE_AS_STPCPY.
- strchr/strchrnul: broadcast+XOR detecting both target char and
null simultaneously. strchrnul reuses strchr via #define.
- strrchr: forward scan recording last match position.
- strncmp: word-at-a-time compare with null detection and counter.
- strcat: strlen(dst) then strcpy(dst_end, src) word-at-a-time.
Each function is independently selectable via CONFIG_RISCV_<FUNC>,
or all enabled together with CONFIG_RISCV_STRING_FUNCTION=y.
Assisted-by: Claude Opus 5 (1M context) <noreply@anthropic.com>
Signed-off-by: ganjing <ganjing@xiaomi.com>
kasan does not instrument the assembly function,
so it is checked in advance before calling.
If Kasan is not turned on, the speed and space will
be almost unchanged under compiler optimization.
Signed-off-by: anjiahao <anjiahao@xiaomi.com>
Most tools used for compliance and SBOM generation use SPDX identifiers
This change brings us a step closer to an easy SBOM generation.
Signed-off-by: Alin Jerpelea <alin.jerpelea@sony.com>
The reason is that libc.h needs to check whether CONFIG is enabled before the corresponding macro is enabled
Error scene:
arm-none-eabi-ld: /home/crafcat7/SSD/xxx/xxx-dev/nuttx/staging/libc.a(arch_libc.o): in function `memmove':
/home/crafcat7/SSD/xxx/xxx-dev/nuttx/libs/libc/machine/arch_libc.c:146: multiple definition of `memmove'; /home/crafcat7/SSD/xxx/xxx-dev/nuttx/staging/libc.a(arch_memmove.o):/home/crafcat7/SSD/xxx/xxx-dev/nuttx/libs/libc/machine/arm/armv8-m/gnu/arch_memmove.S:56: first defined here
Signed-off-by: chenrun1 <chenrun1@xiaomi.com>
__dtoa is not used because currently NuttX uses other
function called __dtoa_engine() to do the same thing
Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>
Provide a way to only customize specific string operations,
such as for memcpy with the DMA capability by ROM.
Signed-off-by: yangdongdong <yangdongdong@xiaomi.com>
Add the `LIBC_PREVENT_STRING_KERNEL` and `LIBC_PREVENT_STRING_USER`
that are meant to be selected by the chip if no libc implementation
is going to be built. If selected, neither NuttX's software version
of the libc nor any architecture-specific implementation will be
built in the kernel or in the userspace, respectively. In this
case, the linker may provide a ROM-defined version of the libc
functions instead.
1.Reduce the default size of task_group_s(~512B each task)
2.Scale better between simple and complex application
Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>
Change-Id: Ia872137504fddcf64d89c48d6f0593d76d582710
drivers/net/ftmac100.c, libs/libc/stdlib/lib_aligned_alloc.c
A continuation of PRs #1507, #1510, and #1512. See Issue #1481 for additional information.
Squashed commit of the following:
libs/libxx: Fix some confusing in naming. If the directory is called libxx, then the library must be libxx.a (unless perhaps LIBCXX is selected).
libs/: Fix paths in moved library directories.
libs: Brute force move of libc, libnx, and libxx to libs. Cannot yet build it in that configuration.
