157 lines
3.4 KiB
C
157 lines
3.4 KiB
C
/*
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* fpr_arith.h
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*
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* Created on: 20/03/2013
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* Author: Eduardo Bezerra - kdubezerra@gmail.com
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*/
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#ifndef FPR_ARITH_H_
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#define FPR_ARITH_H_
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/* FIXED POINT REAL
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This header contains the definition of the FPReal type, which
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is a signed 32 bits integer. It has the following structure:
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32 bits:
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1 for sign
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17 for integer part
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14 for fractional part
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See section B.6 of Pintos documentation for a detailed explanation:
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http://www2.icorsi.ch/mod/resource/view.php?id=91264
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*/
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/* Fixed-point real type. */
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typedef int FPReal;
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/* Number of bits reserved for the fractional part. */
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#define FRACBITS 14
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/* Convert an FPReal to int */
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static inline int FPR_TO_INT (FPReal fpr);
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/* Convert an int to FPReal */
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static inline FPReal INT_TO_FPR (int);
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/* Increment an FPReal by 1 */
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static inline FPReal FPR_INC (FPReal *);
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/* Add two FPReals */
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static inline FPReal FPR_ADD_FPR (FPReal, FPReal);
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/* Subtract one FPReal from another */
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static inline FPReal FPR_SUB_FPR (FPReal, FPReal);
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/* Multiply an FPReal by an int */
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static inline FPReal FPR_MUL_INT (FPReal, int);
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/* Divide an FPReal by an int */
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static inline FPReal FPR_DIV_INT (FPReal, int);
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/* Add an int to an FPReal */
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static inline FPReal FPR_ADD_INT (FPReal, int);
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/* Subtract an int from an FPReal */
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static inline FPReal FPR_SUB_INT (FPReal, int);
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/* Multiply two FPReals */
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static inline FPReal FPR_MUL_FPR (FPReal, FPReal);
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/* Divide an FPReal by another */
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static inline FPReal FPR_DIV_FPR (FPReal, FPReal);
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/* Divide two ints and return the real result as an FPReal */
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static inline FPReal INT_DIV_INT (int, int);
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/* ==================================*/
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/* FPReal functions implementations. */
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/* Convert an FPReal to int */
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static inline int
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FPR_TO_INT (FPReal fpr) {
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return fpr >> FRACBITS;
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}
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/* Convert an int to FPReal */
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static inline FPReal
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INT_TO_FPR (int i) {
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return i << FRACBITS;
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}
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/* Increment an FPReal by 1 */
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static inline
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FPReal FPR_INC (FPReal * fpr) {
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(*fpr) += (1 << FRACBITS);
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return *fpr;
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}
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/* Add two FPReals */
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static inline
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FPReal FPR_ADD_FPR (FPReal fpr_a, FPReal fpr_b) {
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return fpr_a + fpr_b;
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}
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/* Subtract one FPReal from another */
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static inline
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FPReal FPR_SUB_FPR (FPReal fpr_a, FPReal fpr_b) {
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return fpr_a - fpr_b;
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}
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/* Multiply an FPReal by an int */
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static inline
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FPReal FPR_MUL_INT (FPReal fpr_a, int b) {
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return fpr_a * b;
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}
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/* Divide an FPReal by an int */
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static inline
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FPReal FPR_DIV_INT (FPReal fpr_a, int b) {
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return fpr_a / b;
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}
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/* Add an int to an FPReal */
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static inline
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FPReal FPR_ADD_INT (FPReal fpr_a, int b) {
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return fpr_a + (b << FRACBITS);
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}
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/* Subtract an int from an FPReal */
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static inline
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FPReal FPR_SUB_INT (FPReal fpr_a, int b) {
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return fpr_a - (b << FRACBITS);
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}
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/* Multiply two FPReals */
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static inline
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FPReal FPR_MUL_FPR (FPReal fpr_a, FPReal fpr_b) {
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int64_t extended_a = fpr_a;
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extended_a *= (int64_t) fpr_b;
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extended_a >>= FRACBITS;
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return (FPReal) extended_a;
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}
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/* Divide an FPReal by another */
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static inline
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FPReal FPR_DIV_FPR (FPReal fpr_a, FPReal fpr_b) {
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int64_t extended_a = fpr_a;
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extended_a <<= FRACBITS;
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extended_a /= (int64_t) fpr_b;
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return (FPReal) extended_a;
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}
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/* Divide two ints and return the real result as an FPReal */
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static inline
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FPReal INT_DIV_INT (int a, int b) {
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int64_t exta = a;
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exta <<= FRACBITS;
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exta /= b;
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return (FPReal) exta;
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}
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#endif /* FPR_ARITH_H_ */
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