common/memsize.c: Simplify RAM size detection

The case of memory of size 0 is not that different from a memory of any other
size, so we remove the duplicate code and treat the small differences when it
is the case.

Signed-off-by: Eddy Petrișor <eddy.petrisor@gmail.com>

diff --git a/common/memsize.c b/common/memsize.c
index 0fb9ba57b62b21d99df1fc8214c67a0016d1e63b..5c0d279625a005484f055e19b8dc7183d2c4dd56 100644 (file)
--- a/common/memsize.c
+++ b/common/memsize.c
@@ -33,38 +33,28 @@ long get_ram_size(long *base, long maxsize)
        long           size;
        int            i = 0;
 
-       for (cnt = (maxsize / sizeof(long)) >> 1; cnt > 0; cnt >>= 1) {
+       for (cnt = (maxsize / sizeof(long)) >> 1; cnt >= 0; cnt >>= 1) {
                addr = base + cnt;      /* pointer arith! */
                sync();
-               save[i++] = *addr;
+               save[i] = *addr;
                sync();
-               *addr = ~cnt;
-       }
-
-       addr = base;
-       sync();
-       save[i] = *addr;
-       sync();
-       *addr = 0;
-
-       sync();
-       if ((val = *addr) != 0) {
-               /* Restore the original data before leaving the function. */
-               sync();
-               *addr = save[i];
-               for (cnt = 1; cnt < maxsize / sizeof(long); cnt <<= 1) {
-                       addr  = base + cnt;
-                       sync();
-                       *addr = save[--i];
+               if (cnt) {
+                       i++;
+                       *addr = ~cnt;
+               } else {
+                       *addr = 0;
                }
-               return (0);
        }
 
-       for (cnt = 1; cnt < maxsize / sizeof(long); cnt <<= 1) {
+       sync();
+       cnt = 0;
+       do {
                addr = base + cnt;      /* pointer arith! */
                val = *addr;
-               *addr = save[--i];
-               if (val != ~cnt) {
+               *addr = save[i--];
+               sync();
+               if (((cnt == 0) && (val != 0)) ||
+                   ((cnt != 0) && (val != ~cnt))) {
                        size = cnt * sizeof(long);
                        /*
                         * Restore the original data
@@ -74,11 +64,16 @@ long get_ram_size(long *base, long maxsize)
                             cnt < maxsize / sizeof(long);
                             cnt <<= 1) {
                                addr  = base + cnt;
-                               *addr = save[--i];
+                               *addr = save[i--];
                        }
                        return (size);
                }
-       }
+
+               if (cnt)
+                       cnt = cnt << 1;
+               else
+                       cnt = 1;
+       } while (cnt < maxsize / sizeof(long));
 
        return (maxsize);
 }