FIX: CRASH when removing 32768 or more bytes from the head of series

Author: Oldes

src/include/sys-value.h

@@ -448,7 +448,7 @@ static REBCNT bit_sizes[4] = { 8, 16, 32, 64 };
 #define VAL_STR_IS_ASCII(v) (VAL_BYTE_SIZE(v) && !Is_Not_ASCII(VAL_BIN_DATA(v), VAL_LEN(v)))
 
 // Bias is empty space in front of head:
-#define	SERIES_BIAS(s)	   (REBCNT)(SERIES_FLAGS(s) >> 16)
+#define	SERIES_BIAS(s)	   (REBCNT)((SERIES_FLAGS(s) >> 16) & 0xffff)
 #define MAX_SERIES_BIAS    0x1000
 #define SERIES_SET_BIAS(s,b) (SERIES_FLAGS(s) = (SERIES_FLAGS(s) & 0xffff) | (b << 16))
 #define SERIES_ADD_BIAS(s,b) (SERIES_FLAGS(s) += (b << 16))

src/tests/units/series-test.r3

@@ -238,6 +238,11 @@ Rebol [
 		--assert 1 = length? b
 		--assert 10 = first b
 
+	--test-- "issue-2397"
+		;@@ https://github.com/rebol/rebol-issues/issues/2397
+		b: make binary! 40000 insert/dup b 0 40000
+		remove/part b to integer! #{8000}
+
 ===end-group===
 
 ===start-group=== "SORT"