diff --git a/src/i_system.h b/src/i_system.h index a3790dca3..a2dd81cca 100644 --- a/src/i_system.h +++ b/src/i_system.h @@ -50,7 +50,7 @@ tic_t I_GetTime(void); */ precise_t I_GetPreciseTime(void); -/** \brief Returns the difference between precise times as microseconds. +/** \brief Converts a precise_t to microseconds and casts it to a 32 bit integer. */ int I_PreciseToMicros(precise_t); diff --git a/src/lua_baselib.c b/src/lua_baselib.c index a0b5ff873..12ad4fee0 100644 --- a/src/lua_baselib.c +++ b/src/lua_baselib.c @@ -31,6 +31,7 @@ #include "m_misc.h" // M_MapNumber #include "b_bot.h" // B_UpdateBotleader #include "d_clisrv.h" // CL_RemovePlayer +#include "i_system.h" // I_GetPreciseTime, I_PreciseToMicros #include "lua_script.h" #include "lua_libs.h" @@ -3879,6 +3880,12 @@ static int lib_gTicsToMilliseconds(lua_State *L) return 1; } +static int lib_getTimeMicros(lua_State *L) +{ + lua_pushinteger(L, I_PreciseToMicros(I_GetPreciseTime())); + return 1; +} + static luaL_Reg lib[] = { {"print", lib_print}, {"chatprint", lib_chatprint}, @@ -4153,6 +4160,8 @@ static luaL_Reg lib[] = { {"G_TicsToCentiseconds",lib_gTicsToCentiseconds}, {"G_TicsToMilliseconds",lib_gTicsToMilliseconds}, + {"getTimeMicros",lib_getTimeMicros}, + {NULL, NULL} }; diff --git a/src/sdl/i_system.c b/src/sdl/i_system.c index 2ec28ebc8..ccec37093 100644 --- a/src/sdl/i_system.c +++ b/src/sdl/i_system.c @@ -2163,7 +2163,13 @@ precise_t I_GetPreciseTime(void) int I_PreciseToMicros(precise_t d) { - return (int)(d / (timer_frequency / 1000000.0)); + // d is going to be converted into a double. So remove the highest bits + // to avoid loss of precision in the lower bits, for the (probably rare) case + // that the higher bits are actually used. + d &= ((precise_t)1 << 53) - 1; // The mantissa of a double can handle 53 bits at most. + // The resulting double from the calculation is converted first to UINT64 to avoid overflow, + // which is undefined behaviour when converting floating point values to integers. + return (int)(UINT64)(d / (timer_frequency / 1000000.0)); } //