2022-09-16 14:41:00

1 files changed, 42 insertions, 0 deletions

diff --git a/source/luametatex/source/tex/texarithmetic.h b/source/luametatex/source/tex/texarithmetic.h
new file mode 100644
index 000000000..53deca36b
--- /dev/null
+++ b/source/luametatex/source/tex/texarithmetic.h
@@ -0,0 +1,42 @@
+/*
+    See license.txt in the root of this project.
+*/
+
+# ifndef LMT_ARITHMETIC_H
+# define LMT_ARITHMETIC_H
+
+/*tex
+
+    Fixed-point arithmetic is done on {\em scaled integers} that are multiples of $2^{-16}$. In
+    other words, a binary point is assumed to be sixteen bit positions from the right end of a
+    binary computer word.
+
+*/
+
+extern scaled tex_multiply_and_add  (int n, scaled x, scaled y, scaled max_answer);
+extern scaled tex_nx_plus_y         (int n, scaled x, scaled y);
+extern scaled tex_multiply_integers (int n, scaled x);
+extern scaled tex_x_over_n_r        (scaled x, int n, int *remainder);
+extern scaled tex_x_over_n          (scaled x, int n);
+extern scaled tex_xn_over_d         (scaled x, int n, int d);
+extern scaled tex_xn_over_d_r       (scaled x, int n, int d, int *remainder);
+/*     scaled tex_divide_scaled     (scaled s, scaled m, int dd); */
+extern scaled tex_divide_scaled_n   (double s, double m, double d);
+extern scaled tex_ext_xn_over_d     (scaled, scaled, scaled);
+extern scaled tex_round_xn_over_d   (scaled x, int n, unsigned int d);
+
+inline static scaled tex_round_decimals_digits(const unsigned char *digits, unsigned k)
+{
+     int a = 0;
+     while (k-- > 0) {
+         a = (a + digits[k] * two) / 10;
+     }
+     return (a + 1) / 2;
+}
+
+inline static int tex_half_scaled(int x)
+{
+    return odd(x) ? ((x + 1) / 2) : (x / 2);
+}
+
+# endif