Rockchip rk27xx utils

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@29936 a1c6a512-1295-4272-9138-f99709370657

1 files changed, 35 insertions, 0 deletions

diff --git a/utils/rk27utils/rk27load/checksum.c b/utils/rk27utils/rk27load/checksum.c
new file mode 100644
index 0000000000..f0fe59350e
--- /dev/null
+++ b/utils/rk27utils/rk27load/checksum.c
@@ -0,0 +1,35 @@
+#include <stdint.h>
+#include "checksum.h"
+
+uint16_t checksum(void *buff, uint32_t size)
+{
+        uint32_t r2 = 0xffff;
+        uint32_t r3 = 0;
+        uint32_t i, j;
+
+        for (i=0; i<size; i++) {
+                r3 = 0x80;
+                for (j=0; j<8; j++) {
+                        if ((r2 & 0x8000) != 0) {
+                                r2 <<= 17;
+                                r2 >>= 16;
+                                r2 ^= 0x1000;
+                                r2 ^= 0x21;
+                        }
+                        else {
+                                r2 <<= 17;
+                                r2 >>= 16;
+                        }
+
+                        if ((((uint8_t *)buff)[i] & r3) != 0) {
+                                r2 ^= 0x1000;
+                                r2 ^= 0x21;
+                        }
+
+                        r3 >>= 1;
+                }
+        }
+
+        return r2 & 0xffff;
+}
+