xiaoxiang781216 commented on code in PR #20996:
URL: https://github.com/apache/nuttx/pull/20996#discussion_r4374093604
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sched/Kconfig:
##########
@@ -1647,7 +1647,6 @@ config ENABLE_PARTIAL_SIGNALS
config DISABLE_ALL_SIGNALS
bool "Disable all signal support"
select DISABLE_POSIX_TIMERS
- select DISABLE_MQUEUE_NOTIFICATION
Review Comment:
let change select to depend on
##########
libs/libc/stream/lib_ultoa_invert.c:
##########
@@ -57,8 +58,55 @@ FAR char *__ultoa_invert(unsigned long long val, FAR char
*str, int base)
{
int v;
+#if defined(CONFIG_DEFAULT_SMALL) && defined(__GNUC__)
Review Comment:
why not always enable optimization by remove `#if`
##########
libs/libc/stream/lib_ultoa_invert.c:
##########
@@ -57,8 +58,55 @@ FAR char *__ultoa_invert(unsigned long long val, FAR char
*str, int base)
{
int v;
+#if defined(CONFIG_DEFAULT_SMALL) && defined(__GNUC__)
+ /* GCC -Os lowers 64-bit division (even by constants) to
+ * __aeabi_uldivmod libcalls, which drag in ~0.9KB of libgcc.
+ */
+
+ if (base > 1 && (base & (base - 1)) == 0)
+ {
+ unsigned int b = (unsigned int)base;
+ unsigned int shift = 0;
+
+ while ((1u << shift) < b)
+ {
+ shift++;
+ }
+
+ v = (int)(val & (b - 1));
+ val >>= shift;
+ }
+ else if (base == 10)
+ {
+ unsigned long long q = val;
+
+ div64_const32(q, 10); /* q = val / 10 (inline umulls) */
Review Comment:
val and remove line 85
##########
libs/libc/stream/lib_ultoa_invert.c:
##########
@@ -38,6 +38,7 @@
****************************************************************************/
#include "lib_ultoa_invert.h"
+#include <nuttx/lib/math32.h>
Review Comment:
move before line 40 with one blank line
##########
include/nuttx/lib/math32.h:
##########
@@ -318,7 +318,7 @@ extern "C"
} \
while (0)
-#if defined(CONFIG_HAVE_EXPRESSION_STATEMENT)
+#if defined(__GNUC__)
Review Comment:
why need change? CONFIG_HAVE_EXPRESSION_STATEMENT is defined in
include/nuttx/compiler.h in automatically.
##########
libs/libc/stream/lib_ultoa_invert.c:
##########
@@ -57,8 +58,55 @@ FAR char *__ultoa_invert(unsigned long long val, FAR char
*str, int base)
{
int v;
+#if defined(CONFIG_DEFAULT_SMALL) && defined(__GNUC__)
+ /* GCC -Os lowers 64-bit division (even by constants) to
+ * __aeabi_uldivmod libcalls, which drag in ~0.9KB of libgcc.
+ */
+
+ if (base > 1 && (base & (base - 1)) == 0)
+ {
+ unsigned int b = (unsigned int)base;
Review Comment:
change to `x >> ffs(base)`
##########
libs/libc/stream/lib_ultoa_invert.c:
##########
@@ -57,8 +58,55 @@ FAR char *__ultoa_invert(unsigned long long val, FAR char
*str, int base)
{
int v;
+#if defined(CONFIG_DEFAULT_SMALL) && defined(__GNUC__)
+ /* GCC -Os lowers 64-bit division (even by constants) to
+ * __aeabi_uldivmod libcalls, which drag in ~0.9KB of libgcc.
+ */
+
+ if (base > 1 && (base & (base - 1)) == 0)
+ {
+ unsigned int b = (unsigned int)base;
+ unsigned int shift = 0;
+
+ while ((1u << shift) < b)
+ {
+ shift++;
+ }
+
+ v = (int)(val & (b - 1));
+ val >>= shift;
+ }
+ else if (base == 10)
+ {
+ unsigned long long q = val;
+
+ div64_const32(q, 10); /* q = val / 10 (inline umulls) */
+ v = (int)(val - q * 10); /* remainder */
+ val = q;
+ }
+ else
Review Comment:
add debug assert instead since caller pass only 8/10/16
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