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--- math:start [2022/07/16 20:22] – [Namespace math::fxp] rajit
+++ math:start [2023/04/25 14:23] (current) – [Functions] rajit
@@ Line 2: / Line 2: @@
 This namespace is used to provide support functions for math operations.
+===== Functions =====
+<code act>
+template<pint Worig, Wnew> function sign_extend (int<Worig> x) : int<Wnew>;
+</code>
+This function takes an integer ''x'' of width ''Worig'', and sign extends its most significant bit to return a result that has width ''Wnew''. It assumes that ''Wnew'' is at least ''Worig.''
+<code act>
+template<pint Worig, Wnew> function zero_extend (int<Worig> x) : int<Wnew>;
+</code>
+This function takes an integer ''x'' of width ''Worig'', and zero extends it to return a result that has width ''Wnew''. It assumes that ''Wnew'' is at least ''Worig.''
 ===== Namespace math::fxp =====
+==== Functions ====
 The ''math::fxp'' namespace contains simple definitions for fixed-point arithmetic functions. Functions take two parameters ''A'' and ''B'', and integers use the standard Q-format where the representation Q(A,B) corresponds to A digits for the integer part and B digits for the fractional part. The representation uses 2's complement for negative
@@ Line 43: / Line 63: @@
 This returns the negated value of a signed Q(A,B) number ''x''.
+<code act>
+template<pint A,B> function positive (int<A+B> x) : bool;
+</code>
+This is true if the fixed point number is positive (greater than zero), and false otherwise.
+<code act>
+template<pint A,B> function negative (int<A+B> x) : bool;
+</code>
+This is true if the fixed point number is negative, and false otherwise
+<code act>
+template<pint A,B> function le(int<A+B> x, y) : bool;
+</code>
+This tests if the value in ''x'' is less than or equal to ''y''.
+<code act>
+function conv_to_fxp(pint A, B; preal v) : pint;
+</code>
+This can be used to convert a real constant value into its fixed point representation. Note that since ''pint'' values are 64-bit wide (max), this only works when ''A+B'' is at most 64.