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feat(libc): implement ffs, ffsl, ffsll, fls and flsll bit search functions #11494

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Merged
oneandonlydean merged 1 commit into from
Oct 27, 2026
Merged

feat(libc): implement ffs, ffsl, ffsll, fls and flsll bit search functions #11494

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5 changes: 5 additions & 0 deletions core/libs/prx/libc/include/Api.hpp
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Original file line number Diff line number Diff line change
Expand Up @@ -941,7 +941,12 @@ const char* APS5_VABI strchr_nid_postfix(const char* s, int c);
char* APS5_VABI index_nid_postfix(const char* s, int c);
char* APS5_VABI strrchr_nid_postfix(const char* s, int c);
char* APS5_VABI rindex_nid_postfix(const char* s, int c);
int APS5_VABI ffs_nid_postfix(int value);
int APS5_VABI ffsl_nid_postfix(std::int64_t value);
int APS5_VABI ffsll_nid_postfix(std::int64_t value);
int APS5_VABI fls_nid_postfix(int mask);
int APS5_VABI flsl_nid_postfix(std::int64_t mask);
int APS5_VABI flsll_nid_postfix(std::int64_t mask);
char* APS5_VABI strstr_nid_postfix(const char* haystack, const char* needle);
size_t APS5_VABI strlcpy_nid_postfix(char* dest, const char* src, size_t size);
std::int64_t APS5_VABI strtol_nid_postfix(const char* str, char** endptr, int base);
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20 changes: 20 additions & 0 deletions core/libs/prx/libc/src/Strings.cpp
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Expand Up @@ -339,10 +339,30 @@ char* APS5_VABI rindex_nid_postfix(const char* s, int c) {
return strrchr_nid_postfix(s, c);
}

int APS5_VABI ffs_nid_postfix(int value) {
return value == 0 ? 0 : std::countr_zero(static_cast<unsigned int>(value)) + 1;
}

int APS5_VABI ffsl_nid_postfix(std::int64_t value) {
return value == 0 ? 0 : std::countr_zero(static_cast<std::uint64_t>(value)) + 1;
}

int APS5_VABI ffsll_nid_postfix(std::int64_t value) {
return value == 0 ? 0 : std::countr_zero(static_cast<std::uint64_t>(value)) + 1;
}

int APS5_VABI fls_nid_postfix(int mask) {
return mask == 0 ? 0 : 32 - std::countl_zero(static_cast<std::uint32_t>(mask));
}

int APS5_VABI flsl_nid_postfix(std::int64_t mask) {
return mask == 0 ? 0 : 64 - std::countl_zero(static_cast<std::uint64_t>(mask));
}

int APS5_VABI flsll_nid_postfix(std::int64_t mask) {
return mask == 0 ? 0 : 64 - std::countl_zero(static_cast<std::uint64_t>(mask));
}

char* APS5_VABI strstr_nid_postfix(const char* haystack, const char* needle) {
return std::strstr(const_cast<char*>(haystack), needle);
}
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10 changes: 10 additions & 0 deletions core/libs/tests/GuestWideStrings.cpp
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Expand Up @@ -400,8 +400,18 @@ int main() {
const char path[] = "a/b/c";
require(rindex_nid_postfix(path, '/') == path + 3 && rindex_nid_postfix(path, 'x') == nullptr);
require(rindex_nid_postfix(path, 0) == path + 5);
require(ffs_nid_postfix(0) == 0 && ffs_nid_postfix(1) == 1 && ffs_nid_postfix(0x80) == 8);
require(ffs_nid_postfix(0x1000) == 13 && ffs_nid_postfix(INT_MIN) == 32 && ffs_nid_postfix(-1) == 1);
require(ffsl_nid_postfix(0) == 0 && ffsl_nid_postfix(1) == 1 && ffsl_nid_postfix(0x80) == 8);
require(ffsl_nid_postfix(0x100000000ll) == 33 && ffsl_nid_postfix(INT64_MIN) == 64 && ffsl_nid_postfix(-1) == 1);
require(ffsll_nid_postfix(0) == 0 && ffsll_nid_postfix(1) == 1 && ffsll_nid_postfix(0x80) == 8);
require(ffsll_nid_postfix(0x100000000ll) == 33 && ffsll_nid_postfix(LLONG_MIN) == 64 && ffsll_nid_postfix(-1) == 1);
require(fls_nid_postfix(0) == 0 && fls_nid_postfix(1) == 1 && fls_nid_postfix(0x80) == 8);
require(fls_nid_postfix(0x40000000) == 31 && fls_nid_postfix(INT_MIN) == 32 && fls_nid_postfix(-1) == 32);
require(flsl_nid_postfix(0) == 0 && flsl_nid_postfix(1) == 1 && flsl_nid_postfix(0x80) == 8);
require(flsl_nid_postfix(0x100000000ll) == 33 && flsl_nid_postfix(INT64_MIN) == 64 && flsl_nid_postfix(-1) == 64);
require(flsll_nid_postfix(0) == 0 && flsll_nid_postfix(1) == 1 && flsll_nid_postfix(0x80) == 8);
require(flsll_nid_postfix(0x100000000ll) == 33 && flsll_nid_postfix(LLONG_MIN) == 64 && flsll_nid_postfix(-1) == 64);
}
return 0;
}
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