Bananymous
/
banan-os
1
1
Fork 1
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

BAN: add pow, log2, log10, log in math 

These are implemented using x86 floating point assembly
This commit is contained in:
Bananymous 2023-05-10 19:03:33 +03:00
parent cae0a1cc60
commit 0d9422ead8
1 changed files with 43 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

43
BAN/include/BAN/Math.h
View File

@ -59,6 +59,49 @@ namespace BAN::Math
return (value & (value - 1)) == 0; return (value & (value - 1)) == 0;
} }
template<floating_point T>
inline constexpr T log2(T value)
{
T result;
asm volatile("fyl2x" : "=t"(result) : "0"(value), "u"((T)1.0) : "st(1)");
return result;
}
template<floating_point T>
inline constexpr T log10(T value)
{
constexpr T INV_LOG_2_10 = 0.3010299956639811952137388947244930267681898814621085413104274611;
T result;
asm volatile("fyl2x" : "=t"(result) : "0"(value), "u"(INV_LOG_2_10) : "st(1)");
return result;
}
template<floating_point T>
inline constexpr T log(T value, T base)
{
return log2(value) / log2(base);
}
template<floating_point T>
inline constexpr T pow(T base, T exp)
{
T result;
asm volatile(
"fyl2x;"
"fld1;"
"fld %%st(1);"
"fprem;"
"f2xm1;"
"faddp;"
"fscale;"
"fxch %%st(1);"
"fstp %%st;"
: "=t"(result)
: "0"(base), "u"(exp)
);
return result;
}
template<integral T> template<integral T>
inline constexpr T little_endian_to_host(const uint8_t* bytes) inline constexpr T little_endian_to_host(const uint8_t* bytes)
{ {