diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/macros.h | 364 |
1 files changed, 351 insertions, 13 deletions
diff --git a/src/macros.h b/src/macros.h index 406ae83da..e7944661a 100644 --- a/src/macros.h +++ b/src/macros.h @@ -5,11 +5,57 @@ #ifndef MACROS_H #define MACROS_H -/* Fetch n bits starting at bit s from x */ +/** + * Fetch n bits from x, started at bit s. + * + * This macro can be used to fetch n bits from the value x. The + * s value set the startposition to read. The startposition is + * count from the LSB and starts at 0. The result starts at a + * LSB, as this isn't just an and-bitmask but also some + * bit-shifting operations. GB(0xFF, 2, 1) will so + * return 0x01 (0000 0001) instead of + * 0x04 (0000 0100). + * + * @param x The value to read some bits. + * @param s The startposition to read some bits. + * @param n The number of bits to read. + * @return The selected bits, aligned to a LSB. + */ #define GB(x, s, n) (((x) >> (s)) & ((1U << (n)) - 1)) -/* Set n bits starting at bit s in x to d */ + +/** Set n bits from x starting at bit s to d + * + * This macro sets n bits from x which started as bit s to the value of + * d. The parameters x, s and n works the same as the parameters of + * #GB. The result is saved in x again. Unused bits in the window + * provided by n are set to 0 if the value of b isn't "big" enough. + * This is not a bug, its a feature. + * + * @note Parameter x must be a variable as the result is saved there. + * @note To avoid unexpecting results the value of b should not use more + * space as the provided space of n bits (log2) + * @param x The variable to change some bits + * @param s The startposition for the new bits + * @param n The size/window for the new bits + * @param d The actually new bits to save in the defined position. + * @return The new value of x + */ #define SB(x, s, n, d) ((x) = ((x) & ~(((1U << (n)) - 1) << (s))) | ((d) << (s))) -/* Add i to the n bits starting at bit s in x */ + +/** Add i to n bits of x starting at bit s. + * + * This add the value of i on n bits of x starting at bit s. The parameters x, + * s, i are similar to #GB besides x must be a variable as the result are + * saved there. An overflow does not affect the following bits of the given + * bit window and is simply ignored. + * + * @note Parameter x must be a variable as the result is saved there. + * @param x The variable to add some bits at some position + * @param s The startposition of the addition + * @param n The size/window for the addition + * @param i The value to add at the given startposition in the given window. + * @return The new value of x + */ #define AB(x, s, n, i) ((x) = ((x) & ~(((1U << (n)) - 1) << (s))) | (((x) + ((i) << (s))) & (((1U << (n)) - 1) << (s)))) #ifdef min @@ -20,23 +66,76 @@ #undef max #endif +/** + * Returns the maximum of two values. + * + * This function returns the greater value of two given values. + * If they are equal the value of a is returned. + * + * @param a The first value + * @param b The second value + * @return The greater value or a if equals + */ template <typename T> static inline T max(T a, T b) { return a >= b ? a : b; } +/** + * Returns the minimum of two values. + * + * This function returns the smaller value of two given values. + * If they are equal the value of b is returned. + * + * @param a The first value + * @param b The second value + * @return The smaller value or b if equals + */ template <typename T> static inline T min(T a, T b) { return a < b ? a : b; } +/** + * Returns the minimum of two integer. + * + * This function returns the smaller value of two given integers. + * + * @param a The first integer + * @param b The second integer + * @return The smaller value + */ static inline int min(int a, int b) { if (a <= b) return a; return b; } +/** + * Returns the minimum of two unsigned integers. + * + * This function returns the smaller value of two given unsigned integers. + * + * @param a The first unsigned integer + * @param b The second unsigned integer + * @return The smaller value + */ static inline uint minu(uint a, uint b) { if (a <= b) return a; return b; } - +/** + * Clamp an integer between an interval. + * + * This function returns a value which is between the given interval of + * min and max. If the given value is in this interval the value itself + * is returned otherwise the border of the interval is returned, according + * which side of the interval was 'left'. + * + * @note The min value must be less or equal of max or you get some + * unexpected results. + * @param a The value to clamp/truncate. + * @param min The minimum of the interval. + * @param max the maximum of the interval. + * @returns A value between min and max which is closest to a. + * @see clampu(uint, uint, uint) + */ static inline int clamp(int a, int min, int max) { if (a <= min) return min; @@ -44,6 +143,22 @@ static inline int clamp(int a, int min, int max) return a; } +/** + * Clamp an unsigned integer between an interval. + * + * This function returns a value which is between the given interval of + * min and max. If the given value is in this interval the value itself + * is returned otherwise the border of the interval is returned, according + * which side of the interval was 'left'. + * + * @note The min value must be less or equal of max or you get some + * unexpected results. + * @param a The value to clamp/truncate. + * @param min The minimum of the interval. + * @param max the maximum of the interval. + * @returns A value between min and max which is closest to a. + * @see clamp(int, int, int) + */ static inline uint clampu(uint a, uint min, uint max) { if (a <= min) return min; @@ -51,7 +166,20 @@ static inline uint clampu(uint a, uint min, uint max) return a; } -/* Gracefully reduce a signed 64-bit int to signed 32-bit -- no bogusly truncating the sign bit */ +/** + * Reduce a signed 64-bit int to a signed 32-bit one + * + * This function clamps a 64-bit integer to a 32-bit integer. + * If the 64-bit value is smaller than the smallest 32-bit integer + * value 0x80000000 this value is returned (the left one bit is the sign bit). + * If the 64-bit value is greater than the greatest 32-bit integer value 0x7FFFFFFF + * this value is returned. In all other cases the 64-bit value 'fits' in a + * 32-bits integer field and so the value is casted to int32 and returned. + * + * @param a The 64-bit value to clamps + * @return The 64-bit value reduced to a 32-bit value + * @see clamp(int, int, int) + */ static inline int32 ClampToI32(int64 a) { if (a <= (int32)0x80000000) return 0x80000000; @@ -59,36 +187,114 @@ static inline int32 ClampToI32(int64 a) return (int32)a; } +/** + * Multiply two integer values and shift the results to right. + * + * This function multiplies two integer values. The result is + * shifted by the amount of shift to right. + * + * @param a The first integer + * @param b The second integer + * @param shift The amount to shift the value to right. + * @return The shifted result + */ static inline int32 BIGMULSS(int32 a, int32 b, int shift) { return (int32)((int64)a * (int64)b >> shift); } +/** + * Multiply two unsigned integers and shift the results to right. + * + * This function multiplies two unsigned integers. The result is + * shifted by the amount of shift to right. + * + * @param a The first unsigned integer + * @param b The second unsigned integer + * @param shift The amount to shift the value to right. + * @return The shifted result + */ static inline uint32 BIGMULUS(uint32 a, uint32 b, int shift) { return (uint32)((uint64)a * (uint64)b >> shift); } +/** + * Checks if a value is between a window started at some base point. + * + * This macro checks if the value x is between the value of base + * and base+size. If x equals base this returns true. If x equals + * base+size this returns false. + * + * @param x The value to check + * @param base The base value of the interval + * @param size The size of the interval + * @return True if the value is in the interval, false else. + */ /* OPT: optimized into an unsigned comparison */ //#define IS_INSIDE_1D(x, base, size) ((x) >= (base) && (x) < (base) + (size)) #define IS_INSIDE_1D(x, base, size) ( (uint)((x) - (base)) < ((uint)(size)) ) +/** + * Checks if a bit in a value is set. + * + * This function checks if a bit inside a value is set or not. + * The y value specific the position of the bit, started at the + * LSB and count from 0. + * + * @param x The value to check + * @param y The position of the bit to check, started from the LSB + * @return True if the bit is set, false else. + */ template<typename T> static inline bool HASBIT(T x, int y) { return (x & ((T)1 << y)) != 0; } +/** + * Set a bit in a variable. + * + * This function sets a bit in a variable. The variable is changed + * and the value is also returned. Parameter y defines the bit and + * starts at the LSB with 0. + * + * @param x The variable to set a bit + * @param y The bit position to set + * @return The new value of the old value with the bit set + */ template<typename T> static inline T SETBIT(T& x, int y) { return x |= (T)1 << y; } +/** + * Clears a bit in a variable. + * + * This function clears a bit in a variable. The variable is + * changed and the value is also returned. Parameter y defines the bit + * to clear and starts at the LSB with 0. + * + * @param x The variable to clear the bit + * @param y The bit position to clear + * @return The new value of the old value with the bit cleared + */ template<typename T> static inline T CLRBIT(T& x, int y) { return x &= ~((T)1 << y); } +/** + * Toggles a bit in a variable. + * + * This function toggles a bit in a variable. The variable is + * changed and the value is also returned. Parameter y defines the bit + * to toggle and starts at the LSB with 0. + * + * @param x The varliable to toggle the bit + * @param y The bit position to toggle + * @return The new value of the old value with the bit toggled + */ template<typename T> static inline T TOGGLEBIT(T& x, int y) { return x ^= (T)1 << y; @@ -96,24 +302,84 @@ template<typename T> static inline T TOGGLEBIT(T& x, int y) /* checking more bits. Maybe unneccessary, but easy to use */ +/** + * Check several bits in a value. + * + * This macro checks if a value contains at least one bit of an other + * value. + * + * @param x The first value + * @param y The second value + * @return True if at least one bit is set in both values, false else. + */ #define HASBITS(x, y) ((x) & (y)) + +/** + * Sets several bits in a variable. + * + * This macro sets several bits in a variable. The bits to set are provided + * by a value. The new value is also returned. + * + * @param x The variable to set some bits + * @param y The value with set bits for setting them in the variable + * @return The new value of x + */ #define SETBITS(x, y) ((x) |= (y)) + +/** + * Clears several bits in a variable. + * + * This macro clears several bits in a variable. The bits to clear are + * provided by a value. The new value is also returned. + * + * @param x The variable to clear some bits + * @param y The value with set bits for clearing them in the variable + * @return The new value of x + */ #define CLRBITS(x, y) ((x) &= ~(y)) #define GENERAL_SPRITE_COLOR(color) ((color) + PALETTE_RECOLOR_START) #define PLAYER_SPRITE_COLOR(owner) (GENERAL_SPRITE_COLOR(_player_colors[owner])) extern const byte _ffb_64[128]; -/* Returns the position of the first bit that is not zero, counted from the - * left. Ie, 10110100 returns 2, 00000001 returns 0, etc. When x == 0 returns + +/** + * Returns the first occure of a bit in a 6-bit value (from right). + * + * Returns the position of the first bit that is not zero, counted from the + * LSB. Ie, 110100 returns 2, 000001 returns 0, etc. When x == 0 returns * 0. + * + * @param x The 6-bit value to check the first zero-bit + * @return The first position of a bit started from the LSB or 0 if x is 0. */ #define FIND_FIRST_BIT(x) _ffb_64[(x)] -/* Returns x with the first bit that is not zero, counted from the left, set - * to zero. So, 10110100 returns 10110000, 00000001 returns 00000000, etc. + +/** + * Returns a value with the first occured of a bit set to zero. + * + * Returns x with the first bit from LSB that is not zero set + * to zero. So, 110100 returns 110000, 000001 returns 000000, etc. + * + * @param x The value to returned a new value + * @return The value which the first bit is set to zero */ #define KILL_FIRST_BIT(x) _ffb_64[(x) + 64] +/** + * Finds the position of the first bit in an integer. + * + * This function returns the position of the first bit set in the + * integer. It does only check the bits of the bitmask + * 0x3F3F (0011111100111111) and checks only the + * bits of the bitmask 0x3F00 if and only if the + * lower part 0x00FF is 0. This results the bits at 0x00C0 must + * be also zero to check the bits at 0x3F00. + * + * @param value The value to check the first bits + * @return The position of the first bit which is set + * @see FIND_FIRST_BIT + */ static inline int FindFirstBit2x64(int value) { /* @@ -131,9 +397,20 @@ Faster ( or at least cleaner ) implementation below? } else { return FIND_FIRST_BIT(GB(value, 0, 6)); } - } +/** + * Clear the first bit in an integer. + * + * This function returns a value where the first bit (from LSB) + * is cleared. This function checks, similar to FindFirstBit2x64, + * the bits at 0x3F3F. + * + * @param value The value to clear the first bit + * @return The new value with the first bit cleared + * @see KILL_FIRST_BIT + * @see FindFirstBit2x64 + */ static inline int KillFirstBit2x64(int value) { if (GB(value, 0, 8) == 0) { @@ -143,16 +420,77 @@ static inline int KillFirstBit2x64(int value) } } -/** returns true if value a has only one bit set to 1 */ +/** + * Returns true if value a has only one bit set to 1 + * + * This macro returns true if only one bit is set. + * + * @param a The value to check + * @return True if only one bit is set, false else + */ #define HAS_SINGLE_BIT(a) ( ((a) & ((a) - 1)) == 0) -/* [min,max), strictly less than */ +/** + * Checks if a byte is in an interval. + * + * This macro returns true if a byte value is in the interval of [min, max). + * + * @param a The byte value to check + * @param min The minimum of the interval + * @param max The maximum of the interval + * @see IS_INSIDE_1D + */ #define IS_BYTE_INSIDE(a, min, max) ((byte)((a) - (min)) < (byte)((max) - (min))) -#define IS_INT_INSIDE(a, min, max) ((uint)((a) - (min)) < (uint)((max) - (min))) +/** + * Checks if an int is in an interval. + * + * This macro returns true if a integer value is in the interval of [min, max). + * + * @param a The integer value to check + * @param min The minimum of the interval + * @param max The maximum of the interval + * @see IS_INSIDE_1D + */ +#define IS_INT_INSIDE(a, min, max) ((uint)((a) - (min)) < (uint)((max) - (min))) +/** + * Flips a coin with a given probability. + * + * This macro can be used to get true or false randomized according to a + * given probability. The parameter a and b create a percent value with + * (a/b). The macro returns true in (a/b) percent. + * + * @param a The numerator of the fraction + * @param b The denominator of the fraction, must of course not be null + * @return True in (a/b) percent + */ #define CHANCE16(a, b) ((uint16)Random() <= (uint16)((65536 * (a)) / (b))) + +/** + * Flips a coin with a given probability and saves the randomize-number in a variable. + * + * This macro uses the same parameters as the CHANCE16 marco. The third parameter + * must be a variable the randomize-number from Random() is saved in. + * + * @param a The numerator of the fraction, see CHANCE16 + * @param b The denominator of the fraction, see CHANCE16 + * @param r The variable to save the randomize-number from Random() + * @return True in (a/b) percent + */ #define CHANCE16R(a, b, r) ((uint16)(r = Random()) <= (uint16)((65536 * (a)) / (b))) + +/** + * Checks if a given randomize-number is below a given probability. + * + * This macro is used to check if the given probability by the fraction of (a/b) + * is greater than the given randomize-number v. + * + * @param a The numerator of the fraction, see CHANCE16 + * @param b The denominator of the fraction, see CHANCE16 + * @param v The given randomize-number + * @return True if v is less or equals (a/b) + */ #define CHANCE16I(a, b, v) ((uint16)(v) <= (uint16)((65536 * (a)) / (b))) |