From: Matt Brown <matthew.brown.dev@gmail.com>
To: linuxppc-dev@lists.ozlabs.org
Subject: [PATCH v2 2/5] powerpc/lib/sstep: Add popcnt instruction emulation
Date: Mon, 24 Jul 2017 11:01:06 +1000 [thread overview]
Message-ID: <20170724010109.21263-2-matthew.brown.dev@gmail.com> (raw)
In-Reply-To: <20170724010109.21263-1-matthew.brown.dev@gmail.com>
This adds emulations for the popcntb, popcntw, and popcntd instructions.
Tested for correctness against the popcnt{b,w,d} instructions on ppc64le.
Signed-off-by: Matt Brown <matthew.brown.dev@gmail.com>
---
v2:
- fixed opcodes
- fixed typecasting
- fixed bitshifting error for both 32 and 64bit arch
---
arch/powerpc/lib/sstep.c | 43 ++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 42 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/lib/sstep.c b/arch/powerpc/lib/sstep.c
index 87d277f..e6a16a3 100644
--- a/arch/powerpc/lib/sstep.c
+++ b/arch/powerpc/lib/sstep.c
@@ -612,6 +612,35 @@ static nokprobe_inline void do_cmpb(struct pt_regs *regs, unsigned long v1,
regs->gpr[rd] = out_val;
}
+/*
+ * The size parameter is used to adjust the equivalent popcnt instruction.
+ * popcntb = 8, popcntw = 32, popcntd = 64
+ */
+static nokprobe_inline void do_popcnt(struct pt_regs *regs, unsigned long v1,
+ int size, int ra)
+{
+ unsigned long long high, low, mask;
+ unsigned int n;
+ int i, j;
+
+ high = 0;
+ low = 0;
+
+ for (i = 0; i < (64 / size); i++) {
+ n = 0;
+ for (j = 0; j < size; j++) {
+ mask = 1UL << (j + (i * size));
+ if (v1 & mask)
+ n++;
+ }
+ if ((i * size) < 32)
+ low |= n << (i * size);
+ else
+ high |= n << ((i * size) - 32);
+ }
+ regs->gpr[ra] = (high << 32) | low;
+}
+
static nokprobe_inline int trap_compare(long v1, long v2)
{
int ret = 0;
@@ -1194,6 +1223,10 @@ int analyse_instr(struct instruction_op *op, struct pt_regs *regs,
regs->gpr[ra] = regs->gpr[rd] & ~regs->gpr[rb];
goto logical_done;
+ case 122: /* popcntb */
+ do_popcnt(regs, regs->gpr[rd], 8, ra);
+ goto logical_done;
+
case 124: /* nor */
regs->gpr[ra] = ~(regs->gpr[rd] | regs->gpr[rb]);
goto logical_done;
@@ -1206,6 +1239,10 @@ int analyse_instr(struct instruction_op *op, struct pt_regs *regs,
regs->gpr[ra] = regs->gpr[rd] ^ regs->gpr[rb];
goto logical_done;
+ case 378: /* popcntw */
+ do_popcnt(regs, regs->gpr[rd], 32, ra);
+ goto logical_done;
+
case 412: /* orc */
regs->gpr[ra] = regs->gpr[rd] | ~regs->gpr[rb];
goto logical_done;
@@ -1217,7 +1254,11 @@ int analyse_instr(struct instruction_op *op, struct pt_regs *regs,
case 476: /* nand */
regs->gpr[ra] = ~(regs->gpr[rd] & regs->gpr[rb]);
goto logical_done;
-
+#ifdef __powerpc64__
+ case 506: /* popcntd */
+ do_popcnt(regs, regs->gpr[rd], 64, ra);
+ goto logical_done;
+#endif
case 922: /* extsh */
regs->gpr[ra] = (signed short) regs->gpr[rd];
goto logical_done;
--
2.9.3
next prev parent reply other threads:[~2017-07-24 1:01 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-07-24 1:01 [PATCH v2 1/5] powerpc/lib/sstep: Add cmpb instruction emulation Matt Brown
2017-07-24 1:01 ` Matt Brown [this message]
2017-07-24 7:36 ` [PATCH v2 2/5] powerpc/lib/sstep: Add popcnt " Segher Boessenkool
2017-07-24 10:28 ` Balbir Singh
2017-07-25 0:53 ` Matt Brown
2017-07-24 1:01 ` [PATCH v2 3/5] powerpc/lib/sstep: Add bpermd " Matt Brown
2017-07-24 1:01 ` [PATCH 4/5] powerpc/lib/sstep: Add prty " Matt Brown
2017-07-24 1:01 ` [PATCH v2 5/5] powerpc/lib/sstep: Add isel " Matt Brown
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