i965: fix 64-bit immediates in brw_inst(_set)_bits

If we tried to get/set something that was exactly 64 bits, we would
try to do (1 << 64) - 1 to calculate the mask which doesn't give us all
1's like we want.

v2 (Iago)
 - Replace ~0 by ~0ull
 - Removed unnecessary parenthesis

v3 (Kristian)
 - Avoid the conditional

Reviewed-by: Iago Toral Quiroga <itoral@igalia.com>
Reviewed-by: Matt Turner <mattst88@gmail.com>
Reviewed-by: Kristian Høgsberg <krh@bitplanet.net>

diff --git a/src/mesa/drivers/dri/i965/brw_inst.h b/src/mesa/drivers/dri/i965/brw_inst.h
index 4ed95c473cd9fe2d6a6d76736729f686ed05059e..b2afe17f95030ff427f1782ad4a667f839bae02b 100644 (file)
--- a/src/mesa/drivers/dri/i965/brw_inst.h
+++ b/src/mesa/drivers/dri/i965/brw_inst.h
@@ -694,7 +694,7 @@ brw_inst_bits(const brw_inst *inst, unsigned high, unsigned low)
    high %= 64;
    low %= 64;
 
-   const uint64_t mask = (1ull << (high - low + 1)) - 1;
+   const uint64_t mask = (~0ul >> (64 - (high - low + 1)));
 
    return (inst->data[word] >> low) & mask;
 }
@@ -713,7 +713,7 @@ brw_inst_set_bits(brw_inst *inst, unsigned high, unsigned low, uint64_t value)
    high %= 64;
    low %= 64;
 
-   const uint64_t mask = ((1ull << (high - low + 1)) - 1) << low;
+   const uint64_t mask = (~0ul >> (64 - (high - low + 1))) << low;
 
    /* Make sure the supplied value actually fits in the given bitfield. */
    assert((value & (mask >> low)) == value);