Re: [Qemu-devel] [PATCH 21/29] target-sparc: allow 256M sized pages

[Richard Henderson]

On 10/01/2016 05:05 AM, Artyom Tarasenko wrote:

+uint64_t mask = 1ULL + ~(8192ULL << 3 * TTE_PGSIZE(tlb->tte));


Not the first time it has appeared in this patch series, but I find the "1 + ~" 
idiom to be strange.  Surely plain old "-" is clearer.



r~

[Qemu-devel] [PATCH 21/29] target-sparc: allow 256M sized pages

[Artyom Tarasenko]

Signed-off-by: Artyom Tarasenko 
---
 target-sparc/mmu_helper.c | 18 +-
 1 file changed, 1 insertion(+), 17 deletions(-)

diff --git a/target-sparc/mmu_helper.c b/target-sparc/mmu_helper.c
index bef63f8..33b48eb 100644
--- a/target-sparc/mmu_helper.c
+++ b/target-sparc/mmu_helper.c
@@ -456,23 +456,7 @@ static inline int ultrasparc_tag_match(SparcTLBEntry *tlb,
uint64_t address, uint64_t context,
hwaddr *physical)
 {
-uint64_t mask;
-
-switch (TTE_PGSIZE(tlb->tte)) {
-default:
-case 0x0: /* 8k */
-mask = 0xe000ULL;
-break;
-case 0x1: /* 64k */
-mask = 0xULL;
-break;
-case 0x2: /* 512k */
-mask = 0xfff8ULL;
-break;
-case 0x3: /* 4M */
-mask = 0xffc0ULL;
-break;
-}
+uint64_t mask = 1ULL + ~(8192ULL << 3 * TTE_PGSIZE(tlb->tte));
 
 /* valid, context match, virtual address match? */
 if (TTE_IS_VALID(tlb->tte) &&
-- 
2.7.2