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git-svn-id: svn://svn.cc65.org/cc65/trunk@2976 b7a2c559-68d2-44c3-8de9-860c34a00d81

diff --git a/include/_6522.h b/include/_6522.h
index c68d268da160eeba01ea28a281bfb215e3533da3..d5dbc5f75d448ed4474cd8b74dfb5d0b5298db73 100644 (file)
--- a/include/_6522.h
+++ b/include/_6522.h
@@ -35,7 +35,11 @@
 
 
 
-/* Define a structure with the via register offsets */
+/* Define a structure with the 6522 register offsets.
+ * NOTE: The timer registers are not declared as 16 bit registers, because
+ * the order in which the two 8 bit halves are written is important, and
+ * the compiler doesn't guarantee any order when writing 16 bit values.
+ */
 struct __6522 {
     unsigned char      prb;            /* Port register B */
     unsigned char      pra;            /* Port register A */

diff --git a/include/_6526.h b/include/_6526.h
index 2e72aec48ed38523af42d1d04ca6a5a4cdced7fe..c04b26d682193dd5646bd88e2c4b9959b6c8dcb8 100644 (file)
--- a/include/_6526.h
+++ b/include/_6526.h
@@ -38,7 +38,11 @@
 
 
 
-/* Define a structure with the 6526 register offsets */
+/* Define a structure with the 6526 register offsets.
+ * NOTE: The timer registers are not declared as 16 bit registers, because
+ * the order in which the two 8 bit halves are written is important, and
+ * the compiler doesn't guarantee any order when writing 16 bit values.
+ */
 struct __6526 {
     unsigned char      pra;            /* Port register A */
     unsigned char      prb;            /* Port register B */