Significantly optimize the bit fade and own addr tests for size, by folding near-identical switch case bodies together, and removing code duplication by merging pattern_fill() and pattern_check(). Also, add a rep stos[lq] path in the bit fade test.

Before:
   text    data     bss     dec     hex filename
   1581       4       0    1585     631 tests/bit_fade.o
   1236       0       0    1236     4d4 tests/own_addr.o

After:
   text    data     bss     dec     hex filename
   1013       4       0    1017     3f9 tests/bit_fade.o
    787       0       0     787     313 tests/own_addr.o

tests/bit_fade.c

@@ -24,11 +24,13 @@
 #include "test_funcs.h"
 #include "test_helper.h"
 
+#define HAND_OPTIMISED  1   // Use hand-optimised assembler code for performance.
+
 //------------------------------------------------------------------------------
 // Private Functions
 //------------------------------------------------------------------------------
 
-static int pattern_fill(int my_cpu, testword_t pattern)
+static int pattern_fill_check(int my_cpu, testword_t pattern, bool check)
 {
     int ticks = 0;
 
@@ -57,9 +59,43 @@ static int pattern_fill(int my_cpu, testword_t pattern)
                 continue;
             }
             test_addr[my_cpu] = (uintptr_t)p;
+            if (!check) {
+#if HAND_OPTIMISED
+#ifdef __x86_64__
+                uint64_t length = pe - p + 1;
+                __asm__  __volatile__ ("\t"
+                    "rep    \n\t"
+                    "stosq  \n\t"
+                    :
+                    : "c" (length), "D" (p), "a" (pattern)
+                    :
+                );
+                p = pe;
+#else
+                uint32_t length = pe - p + 1;
+                __asm__  __volatile__ ("\t"
+                    "rep    \n\t"
+                    "stosl  \n\t"
+                    :
+                    : "c" (length), "D" (p), "a" (pattern)
+                    :
+                );
+                p = pe;
+#endif
+#else
                 do {
                     write_word(p, pattern);
                 } while (p++ < pe); // test before increment in case pointer overflows
+#endif
+            }
+            else {
+                do {
+                    testword_t actual = read_word(p);
+                    if (unlikely(actual != pattern)) {
+                        data_error(p, pattern, actual, true);
+                    }
+                } while (p++ < pe); // test before increment in case pointer overflows
+            }
             do_tick(my_cpu);
             BAILOUT;
         } while (!at_end && ++pe); // advance pe to next start point
@@ -70,7 +106,7 @@ static int pattern_fill(int my_cpu, testword_t pattern)
     return ticks;
 }
 
-static int pattern_check(int my_cpu, testword_t pattern)
+/*static int pattern_check(int my_cpu, testword_t pattern)
 {
     int ticks = 0;
 
@@ -107,7 +143,7 @@ static int pattern_check(int my_cpu, testword_t pattern)
     }
 
     return ticks;
-}
+}*/
 
 static int fade_delay(int my_cpu, int sleep_secs)
 {
@@ -143,9 +179,13 @@ int test_bit_fade(int my_cpu, int stage, int sleep_secs)
 
     int ticks = 0;
 
+    testword_t pattern = stage < 3 ? all_zero : all_ones;
+
+    stage %= 3;
+
     switch (stage) {
       case 0:
-        ticks = pattern_fill(my_cpu, all_zero);
+        ticks = pattern_fill_check(my_cpu, pattern, false);
         break;
       case 1:
         // Only sleep once.
@@ -154,19 +194,7 @@ int test_bit_fade(int my_cpu, int stage, int sleep_secs)
         }
         break;
       case 2:
-        ticks = pattern_check(my_cpu, all_zero);
+        ticks = pattern_fill_check(my_cpu, pattern, true);
-        break;
-      case 3:
-        ticks = pattern_fill(my_cpu, all_ones);
-        break;
-      case 4:
-        // Only sleep once.
-        if (stage != last_stage) {
-            ticks = fade_delay(my_cpu, sleep_secs);
-        }
-        break;
-      case 5:
-        ticks = pattern_check(my_cpu, all_ones);
         break;
       default:
         break;

tests/own_addr.c

@@ -28,7 +28,7 @@
 // Private Functions
 //------------------------------------------------------------------------------
 
-static int pattern_fill(int my_cpu, testword_t offset)
+static int __attribute__((noclone)) pattern_fill_check(int my_cpu, testword_t offset, bool check)
 {
     int ticks = 0;
 
@@ -58,9 +58,20 @@ static int pattern_fill(int my_cpu, testword_t offset)
                 continue;
             }
             test_addr[my_cpu] = (uintptr_t)p;
+            if (!check) {
                 do {
                     write_word(p, (testword_t)p + offset);
                 } while (p++ < pe); // test before increment in case pointer overflows
+            }
+            else {
+                do {
+                    testword_t expect = (testword_t)p + offset;
+                    testword_t actual = read_word(p);
+                    if (unlikely(actual != expect)) {
+                        data_error(p, expect, actual, true);
+                    }
+                } while (p++ < pe); // test before increment in case pointer overflows
+            }
             do_tick(my_cpu);
             BAILOUT;
         } while (!at_end && ++pe); // advance pe to next start point
@@ -71,7 +82,7 @@ static int pattern_fill(int my_cpu, testword_t offset)
     return ticks;
 }
 
-static int pattern_check(int my_cpu, testword_t offset)
+/*static int pattern_check(int my_cpu, testword_t offset)
 {
     int ticks = 0;
 
@@ -110,18 +121,17 @@ static int pattern_check(int my_cpu, testword_t offset)
     }
 
     return ticks;
-}
+}*/
 
 //------------------------------------------------------------------------------
 // Public Functions
 //------------------------------------------------------------------------------
 
-int test_own_addr1(int my_cpu)
+int test_own_addr1(int my_cpu, int stage)
 {
     int ticks = 0;
 
-    ticks += pattern_fill(my_cpu, 0);
+    ticks += pattern_fill_check(my_cpu, 0, !!stage);
-    ticks += pattern_check(my_cpu, 0);
 
     return ticks;
 }
@@ -143,16 +153,7 @@ int test_own_addr2(int my_cpu, int stage)
     offset /= VM_WINDOW_SIZE;
 #endif
 
-    switch (stage) {
+    ticks = pattern_fill_check(my_cpu, offset, !!stage);
-      case 0:
-        ticks = pattern_fill(my_cpu, offset);
-        break;
-      case 1:
-        ticks = pattern_check(my_cpu, offset);
-        break;
-      default:
-        break;
-    }
 
     return ticks;
 }

tests/test_funcs.h

@@ -17,7 +17,7 @@
 
 int test_addr_walk1(int my_cpu);
 
-int test_own_addr1(int my_cpu);
+int test_own_addr1(int my_cpu, int stage);
 
 int test_own_addr2(int my_cpu, int stage);
 

tests/tests.c

@@ -51,7 +51,7 @@
 test_pattern_t test_list[NUM_TEST_PATTERNS] = {
     // ena,  cpu, stgs, itrs, errs, description
     { true,  SEQ,    1,    6,    0, "[Address test, walking ones, no cache] "},
-    {false,  SEQ,    1,    6,    0, "[Address test, own address in window]  "},
+    {false,  SEQ,    2,    6,    0, "[Address test, own address in window]  "},
     { true,  SEQ,    2,    6,    0, "[Address test, own address + window]   "},
     { true,  PAR,    1,    6,    0, "[Moving inversions, 1s & 0s]           "},
     { true,  PAR,    1,    3,    0, "[Moving inversions, 8 bit pattern]     "},
@@ -124,7 +124,7 @@ int run_test(int my_cpu, int test, int stage, int iterations)
 
         // Address test, own address in window.
       case 1:
-        ticks += test_own_addr1(my_cpu);
+        ticks += test_own_addr1(my_cpu, stage);
         BAILOUT;
         break;