--- /dev/null
+/* -*-c-*-
+ *
+ * $Id: gfx-sqr.c,v 1.1 2000/10/08 15:49:37 mdw Exp $
+ *
+ * Sqaring binary polynomials
+ *
+ * (c) 2000 Straylight/Edgeware
+ */
+
+/*----- Licensing notice --------------------------------------------------*
+ *
+ * This file is part of Catacomb.
+ *
+ * Catacomb is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Library General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or (at your option) any later version.
+ *
+ * Catacomb is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with Catacomb; if not, write to the Free
+ * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
+ * MA 02111-1307, USA.
+ */
+
+/*----- Revision history --------------------------------------------------*
+ *
+ * $Log: gfx-sqr.c,v $
+ * Revision 1.1 2000/10/08 15:49:37 mdw
+ * First glimmerings of binary polynomial arithmetic.
+ *
+ */
+
+/*----- Header files ------------------------------------------------------*/
+
+#include "mpx.h"
+/* #include "gfx.h" */
+#include "gfx-sqr-tab.h"
+
+/*----- Static variables --------------------------------------------------*/
+
+static uint16 tab[256] = GFX_SQRTAB;
+
+/*----- Main code ---------------------------------------------------------*/
+
+/* --- @gfx_sqr@ --- *
+ *
+ * Arguments: @mpw *dv, *dvl@ = destination vector base and limit
+ * @const mpw *av, *avl@ = argument vector base and limit
+ *
+ * Returns: ---
+ *
+ * Use: Performs squaring of binary polynomials.
+ */
+
+void gfx_sqr(mpw *dv, mpw *dvl, const mpw *av, const mpw *avl)
+{
+ mpd a = 0, aa = 0;
+ unsigned b = 0, bb = 0;
+
+ /* --- Simple stuff --- */
+
+ if (dv >= dvl)
+ return;
+ MPX_SHRINK(av, avl);
+
+ /* --- The main algorithm --- *
+ *
+ * Our method depends on the fact that, in a field of characteristic 2, we
+ * have that %$(a + b)^2 = a^2 + b^2$%. Thus, to square a polynomial, it's
+ * sufficient just to put a zero bit between each of the bits of the
+ * original argument. We use a precomputed table for this, and work on
+ * entire octets at a time. Life is more complicated because we've got to
+ * be careful of bizarre architectures which don't have words with a
+ * multiple of 8 bits in them.
+ */
+
+ for (;;) {
+
+ /* --- Input buffering --- */
+
+ if (b < 8) {
+ if (av >= avl)
+ break;
+ a |= *av++ << b;
+ b += MPW_BITS;
+ }
+
+ /* --- Do the work in the middle --- */
+
+ aa |= (mpd)(tab[U8(a)]) << bb;
+ bb += 16;
+ a >>= 8;
+ b -= 8;
+
+ /* --- Output buffering --- */
+
+ if (bb > MPW_BITS) {
+ *dv++ = MPW(aa);
+ if (dv >= dvl)
+ return;
+ aa >>= MPW_BITS;
+ bb -= MPW_BITS;
+ }
+ }
+
+ /* --- Flush the input buffer --- */
+
+ if (b) for (;;) {
+ aa |= (mpd)(tab[U8(a)]) << bb;
+ bb += 16;
+ if (bb > MPW_BITS) {
+ *dv++ = MPW(aa);
+ if (dv >= dvl)
+ return;
+ aa >>= MPW_BITS;
+ bb -= MPW_BITS;
+ }
+ a >>= 8;
+ if (b <= 8)
+ break;
+ else
+ b -= 8;
+ }
+
+ /* --- Flush the output buffer --- */
+
+ if (bb) for (;;) {
+ *dv++ = MPW(aa);
+ if (dv >= dvl)
+ return;
+ aa >>= MPW_BITS;
+ if (bb <= MPW_BITS)
+ break;
+ else
+ bb -= MPW_BITS;
+ }
+
+ /* --- Zero the rest of everything --- */
+
+ MPX_ZERO(dv, dvl);
+}
+
+/*----- Test rig ----------------------------------------------------------*/
+
+#ifdef TEST_RIG
+
+#include <mLib/alloc.h>
+#include <mLib/dstr.h>
+#include <mLib/quis.h>
+#include <mLib/testrig.h>
+
+#define ALLOC(v, vl, sz) do { \
+ size_t _sz = (sz); \
+ mpw *_vv = xmalloc(MPWS(_sz)); \
+ mpw *_vvl = _vv + _sz; \
+ (v) = _vv; \
+ (vl) = _vvl; \
+} while (0)
+
+#define LOAD(v, vl, d) do { \
+ const dstr *_d = (d); \
+ mpw *_v, *_vl; \
+ ALLOC(_v, _vl, MPW_RQ(_d->len)); \
+ mpx_loadb(_v, _vl, _d->buf, _d->len); \
+ (v) = _v; \
+ (vl) = _vl; \
+} while (0)
+
+#define MAX(x, y) ((x) > (y) ? (x) : (y))
+
+static void dumpmp(const char *msg, const mpw *v, const mpw *vl)
+{
+ fputs(msg, stderr);
+ MPX_SHRINK(v, vl);
+ while (v < vl)
+ fprintf(stderr, " %08lx", (unsigned long)*--vl);
+ fputc('\n', stderr);
+}
+
+static int vsqr(dstr *v)
+{
+ mpw *a, *al;
+ mpw *b, *bl;
+ mpw *d, *dl;
+ int ok = 1;
+
+ LOAD(a, al, &v[0]);
+ LOAD(b, bl, &v[1]);
+ ALLOC(d, dl, 2 * (al - a));
+
+ gfx_sqr(d, dl, a, al);
+ if (!mpx_ueq(d, dl, b, bl)) {
+ fprintf(stderr, "\n*** vsqr failed\n");
+ dumpmp(" a", a, al);
+ dumpmp("expected", b, bl);
+ dumpmp(" result", d, dl);
+ ok = 0;
+ }
+
+ free(a); free(b); free(d);
+ return (ok);
+}
+
+static test_chunk defs[] = {
+ { "sqr", vsqr, { &type_hex, &type_hex, 0 } },
+ { 0, 0, { 0 } }
+};
+
+int main(int argc, char *argv[])
+{
+ test_run(argc, argv, defs, SRCDIR"/tests/gfx");
+ return (0);
+}
+
+#endif
+
+/*----- That's all, folks -------------------------------------------------*/
projects / u / mdw / catacomb / blobdiff