added tests as prepared by oliver

test/ref/cc65101102.c

@@ -0,0 +1,56 @@
+/*
+  !!DESCRIPTION!!
+  !!ORIGIN!!      testsuite
+  !!LICENCE!!     Public Domain
+  !!AUTHOR!!      Marc 'BlackJack' Rintsch
+*/
+
+/*
+Compiler is build from cc65-snapshot-2.13.9.20101031 sources.
+
+Expected results and also what I get from this without any optimisations
+are: 48663 and 49218
+
+When I turn on ``-O``: 58096 and 58096.  After swapping the two variable
+declaration lines in `calculate_checksum()` the results are correct
+with ``-O``.
+
+But with ``--O --static-locals`` the results are incorrect again (31757
+and 15408).  ``--static-locals`` alone works though.
+*/
+
+#include <stdio.h>
+#include <stdint.h>
+
+// uint16_t __fastcall__ calculate_checksum(uint8_t *block);
+uint8_t block[256];
+
+uint16_t calculate_checksum(uint8_t *block)
+{
+    uint16_t i, result = 0xffff;
+    uint8_t j;
+
+    for (i = 0; i < 256; ++i) {
+        result ^= block[i] << 8;
+        for (j = 0; j < 8; ++j) {
+            if (result & (1 << 15)) {
+                result = (result << 1) ^ 0x1021;
+            } else {
+                result <<= 1;
+            }
+        }
+    }
+    return ~result;
+}
+
+int main(void)
+{
+    uint16_t i;
+
+    printf("zeroes: %u\n", calculate_checksum(block));
+    for (i = 0; i < 256; ++i) block[i] = i;
+    printf("0..255: %u\n", calculate_checksum(block));
+
+    return 0;
+}
+