bitops.h: improve sign extending API

[Martin Kepplinger]

PATCH 1/2 improves the doc of sign_extend32()

This should help to avoid different manual approaches to sign extension


PATCH 2/2 adds sign_extend64()

An informal example of what could follow in
arch/sh/kernel/traps_64.c after PATCH 2/2:

@@ -101,7 +102,7 @@ static int generate_and_check_address(struct pt_regs *regs,
                __s64 displacement;
                displacement = (opcode >> 10) & 0x3ff;
-               displacement = ((displacement << 54) >> 54); /* sign extend */
+               displacement = sign_extend64(displacement, 9);
                addr = (__u64)((__s64)base_address + (displacement << width_shift));
        } else {


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/