summaryrefslogtreecommitdiff
path: root/n/avr/modules/utils/byte.h
diff options
context:
space:
mode:
Diffstat (limited to 'n/avr/modules/utils/byte.h')
-rw-r--r--n/avr/modules/utils/byte.h100
1 files changed, 100 insertions, 0 deletions
diff --git a/n/avr/modules/utils/byte.h b/n/avr/modules/utils/byte.h
new file mode 100644
index 0000000..436e005
--- /dev/null
+++ b/n/avr/modules/utils/byte.h
@@ -0,0 +1,100 @@
+#ifndef byte_h
+#define byte_h
+/* byte.h */
+/* avr.utils - Utilities AVR module. {{{
+ *
+ * Copyright (C) 2005 Nicolas Schodet
+ *
+ * Robot APB Team/Efrei 2006.
+ * Web: http://assos.efrei.fr/robot/
+ * Email: robot AT efrei DOT fr
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ *
+ * }}} */
+
+/** WARNING: Theses functions only works on little endian processor, do not
+ * use them on other processors, prefer the portable bit shifts and or. This
+ * file only exist to overide bad code production with avr-gcc in the bit
+ * shifts idiom. */
+
+/* Union needed for byte access. */
+union _utils_byte_access
+{
+ uint8_t v8[4];
+ uint16_t v16[2];
+ uint32_t v32;
+};
+
+/** Byte packing macro, pack 4 bytes into a double word. */
+extern inline uint32_t
+v8_to_v32 (uint8_t b3, uint8_t b2, uint8_t b1, uint8_t b0)
+{
+ union _utils_byte_access ba;
+ ba.v8[0] = b0;
+ ba.v8[1] = b1;
+ ba.v8[2] = b2;
+ ba.v8[3] = b3;
+ return ba.v32;
+}
+
+/** Byte packing macro, pack 2 bytes into a word. */
+extern inline uint16_t
+v8_to_v16 (uint8_t b1, uint8_t b0)
+{
+ union _utils_byte_access ba;
+ ba.v8[0] = b0;
+ ba.v8[1] = b1;
+ return ba.v16[0];
+}
+
+/** Word packing macro, pack 2 words into a double word. */
+extern inline uint32_t
+v16_to_v32 (uint16_t w1, uint16_t w0)
+{
+ union _utils_byte_access ba;
+ ba.v16[0] = w0;
+ ba.v16[1] = w1;
+ return ba.v32;
+}
+
+/** Byte unpacking macro, extract one specified byte from a double word. */
+extern inline uint8_t
+v32_to_v8 (uint32_t d, int pos)
+{
+ union _utils_byte_access ba;
+ ba.v32 = d;
+ return ba.v8[pos];
+}
+
+/** Byte unpacking macro, extract one specified byte from a word. */
+extern inline uint8_t
+v16_to_v8 (uint16_t w, int pos)
+{
+ union _utils_byte_access ba;
+ ba.v16[0] = w;
+ return ba.v8[pos];
+}
+
+/** Word unpacking macro, extract one specified word from a double word. */
+extern inline uint16_t
+v32_to_v16 (uint32_t d, int pos)
+{
+ union _utils_byte_access ba;
+ ba.v32 = d;
+ return ba.v16[pos];
+}
+
+#endif /* byte_h */