From: ian <ian>
Date: Sun, 2 Jan 2005 17:45:07 +0000 (+0000)
Subject: encoding bugfixes
X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ijackson/git?a=commitdiff_plain;h=d1aec7cefec536ed607c03066232478c7f3d35df;p=trains.git

encoding bugfixes
---

diff --git a/hostside/nmra.c b/hostside/nmra.c
index a0d3b81..443f235 100644
--- a/hostside/nmra.c
+++ b/hostside/nmra.c
@@ -7,32 +7,33 @@
 void nmra_transmit(const Byte *nmra_packet, int length) {
   Byte encoded[COMMAND_ENCODED_MAX], *encp;
   unsigned working;
-  int working_bits;
+  int working_qty;
 
   assert(length <= NMRA_PACKET_MAX);
   encp= encoded;
-  working= 0xfffc;   /* 16-bit temp register.  Top working_bits bits   */
-  working_bits= 14;  /*  are some data bits to encode, rest are clear. */
+  working= 0xfffc;   /* 16-bit temp register.  Top working_qty bits    */
+  working_qty= 14;   /*  are some data bits to encode, rest are clear. */
   for (;;) {
-    assert(working_bits >= 0);
-    if (working_bits < 7) {
+    assert(working_qty >= 0);
+    if (working_qty < 7) {
       if (length > 0) {
 	/* plonk new data bits just to right of old data bits */
-	working |= (*nmra_packet++ << (8-working_bits));
+	working |= (*nmra_packet++ << (8-working_qty));
 	length--;
-	working_bits += 8;
-      } else if (!working_bits) {
+	working_qty += 8;
+      } else if (!working_qty) {
 	/* all done */
 	break;
       } else {
 	/* pad with exactly enough 1 bits to make up the encoded byte */
-	working |= 0xffU << (8-working_bits);
-	working_bits= 7;
+	working |= 0xffU << (8-working_qty);
+	working_qty= 7;
       }
     }
     assert(encp < encoded + COMMAND_ENCODED_MAX);
-    *encp++= (working_bits >> 8) & 0xfe; /* top 7 bits, shifted left one */
-    working_bits -= 7;
+    *encp++= (working >> 8) & 0xfe; /* top 7 bits, shifted left one */
+    working <<= 7;
+    working_qty -= 7;
   }
   assert(encp > encoded);
   encp[-1] |= 0x01; /* `end of command' bit */