[PATCH v2 0/3] Add support for divde[.] and divdeu[.] instruction emulation

[PATCH v2 0/3] Add support for divde[.] and divdeu[.] instruction emulation

[Balamuruhan S]

Hi All,

This patchset adds support to emulate divde, divde., divdeu and divdeu.
instructions and testcases for it.

Changes in v2:
-------------
* Fix review comments from Paul to make divde_dot and divdeu_dot simple
  by using divde and divdeu, then goto `arith_done` instead of
  `compute_done`.
* Include `Reviewed-by` tag from Sandipan Das.
* Rebase with recent mpe's merge tree.

I would request for your review and suggestions for making it better.

Boot Log:
--------

:: ::
:: ::
[    2.777518] emulate_step_test: divde          : RA = LONG_MIN, RB = LONG_MIN                         PASS
[    2.777882] emulate_step_test: divde          : RA = 1L, RB = 0					PASS
[    2.778432] emulate_step_test: divde          : RA = LONG_MIN, RB = LONG_MAX                         PASS
[    2.778880] emulate_step_test: divde.         : RA = LONG_MIN, RB = LONG_MIN                         PASS
[    2.780172] emulate_step_test: divde.         : RA = 1L, RB = 0					PASS
[    2.780582] emulate_step_test: divde.         : RA = LONG_MIN, RB = LONG_MAX                         PASS
[    2.780983] emulate_step_test: divdeu         : RA = LONG_MIN, RB = LONG_MIN                         PASS
[    2.781276] emulate_step_test: divdeu         : RA = 1L, RB = 0					PASS
[    2.781579] emulate_step_test: divdeu         : RA = LONG_MIN, RB = LONG_MAX                         PASS
[    2.781820] emulate_step_test: divdeu         : RA = LONG_MAX - 1, RB = LONG_MAX                     PASS
[    2.782056] emulate_step_test: divdeu         : RA = LONG_MIN + 1, RB = LONG_MIN                     PASS
[    2.782296] emulate_step_test: divdeu.        : RA = LONG_MIN, RB = LONG_MIN                         PASS
[    2.782556] emulate_step_test: divdeu.        : RA = 1L, RB = 0					PASS
[    2.783502] emulate_step_test: divdeu.        : RA = LONG_MIN, RB = LONG_MAX                         PASS
[    2.783748] emulate_step_test: divdeu.        : RA = LONG_MAX - 1, RB = LONG_MAX                     PASS
[    2.783973] emulate_step_test: divdeu.        : RA = LONG_MIN + 1, RB = LONG_MIN                     PASS
[    2.789617] registered taskstats version 1
[    2.794779] printk: console [netcon0] enabled
[    2.794931] netconsole: network logging started
[    2.795327] hctosys: unable to open rtc device (rtc0)
[    2.953449] Freeing unused kernel memory: 5120K
[    2.953639] This architecture does not have kernel memory protection.
[    2.953918] Run /init as init process
[    3.173573] mount (54) used greatest stack depth: 12576 bytes left
[    3.252465] mount (55) used greatest stack depth: 12544 bytes left

Welcome to Buildroot
buildroot login:

Balamuruhan S (3):
  powerpc ppc-opcode: add divde, divde_dot, divdeu and divdeu_dot
    opcodes
  powerpc sstep: add support for divde[.] and divdeu[.] instructions
  powerpc test_emulate_step: add testcases for divde[.] and divdeu[.]
    instructions

 arch/powerpc/include/asm/ppc-opcode.h |  10 +++
 arch/powerpc/lib/sstep.c              |  13 ++-
 arch/powerpc/lib/test_emulate_step.c  | 164 ++++++++++++++++++++++++++++++++++
 3 files changed, 186 insertions(+), 1 deletion(-)


base-commit: 20862247a368dbb75d6e97d82345999adaacf3cc
-- 
2.14.5

[PATCH v2 1/3] powerpc ppc-opcode: add divde, divde_dot, divdeu and divdeu_dot opcodes

[Balamuruhan S]

include instruction opcodes for divde, divde_dot, divideu and
divideu_dot as macros.

Reviewed-by: Sandipan Das <sandipan@linux.ibm.com>
Signed-off-by: Balamuruhan S <bala24@linux.ibm.com>
---
 arch/powerpc/include/asm/ppc-opcode.h | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/arch/powerpc/include/asm/ppc-opcode.h b/arch/powerpc/include/asm/ppc-opcode.h
index c1df75edde44..0acd01afd5b7 100644
--- a/arch/powerpc/include/asm/ppc-opcode.h
+++ b/arch/powerpc/include/asm/ppc-opcode.h
@@ -339,6 +339,10 @@
 #define PPC_INST_DIVWU			0x7c000396
 #define PPC_INST_DIVD			0x7c0003d2
 #define PPC_INST_DIVDU			0x7c000392
+#define PPC_INST_DIVDE			0x7c000352
+#define PPC_INST_DIVDE_DOT		0x7c000353
+#define PPC_INST_DIVDEU			0x7c000312
+#define PPC_INST_DIVDEU_DOT		0x7c000313
 #define PPC_INST_RLWINM			0x54000000
 #define PPC_INST_RLWINM_DOT		0x54000001
 #define PPC_INST_RLWIMI			0x50000000
@@ -439,6 +443,12 @@
 					__PPC_RA(a) | __PPC_RB(b))
 #define	PPC_DCBZL(a, b)		stringify_in_c(.long PPC_INST_DCBZL | \
 					__PPC_RA(a) | __PPC_RB(b))
+#define PPC_DIVDE(t, a, b)	stringify_in_c(.long PPC_INST_DIVDE	| \
+					___PPC_RT(t) | ___PPC_RA(a)	| \
+					___PPC_RB(b))
+#define PPC_DIVDEU(t, a, b)	stringify_in_c(.long PPC_INST_DIVDEU	| \
+					___PPC_RT(t) | ___PPC_RA(a)	| \
+					___PPC_RB(b))
 #define PPC_LQARX(t, a, b, eh)	stringify_in_c(.long PPC_INST_LQARX | \
 					___PPC_RT(t) | ___PPC_RA(a) | \
 					___PPC_RB(b) | __PPC_EH(eh))
-- 
2.14.5

[PATCH v2 2/3] powerpc sstep: add support for divde[.] and divdeu[.] instructions

[Balamuruhan S]

This patch adds emulation support for divde, divdeu instructions,
	* Divide Doubleword Extended (divde[.])
	* Divide Doubleword Extended Unsigned (divdeu[.])

Reviewed-by: Sandipan Das <sandipan@linux.ibm.com>
Signed-off-by: Balamuruhan S <bala24@linux.ibm.com>
---
 arch/powerpc/lib/sstep.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/lib/sstep.c b/arch/powerpc/lib/sstep.c
index c077acb983a1..2cac71a71878 100644
--- a/arch/powerpc/lib/sstep.c
+++ b/arch/powerpc/lib/sstep.c
@@ -1736,7 +1736,18 @@ int analyse_instr(struct instruction_op *op, const struct pt_regs *regs,
 			op->val = (int) regs->gpr[ra] /
 				(int) regs->gpr[rb];
 			goto arith_done;
-
+#ifdef __powerpc64__
+		case 425:	/* divde[.] */
+			asm volatile(PPC_DIVDE(%0, %1, %2) :
+				"=r" (op->val) : "r" (regs->gpr[ra]),
+				"r" (regs->gpr[rb]));
+			goto arith_done;
+		case 393:	/* divdeu[.] */
+			asm volatile(PPC_DIVDEU(%0, %1, %2) :
+				"=r" (op->val) : "r" (regs->gpr[ra]),
+				"r" (regs->gpr[rb]));
+			goto arith_done;
+#endif
 		case 755:	/* darn */
 			if (!cpu_has_feature(CPU_FTR_ARCH_300))
 				return -1;
-- 
2.14.5

[PATCH v2 3/3] powerpc test_emulate_step: add testcases for divde[.] and divdeu[.] instructions

[Balamuruhan S]

add testcases for divde, divde., divdeu, divdeu. emulated
instructions to cover few scenarios,
        * with same dividend and divisor to have undefine RT
          for divdeu[.]
        * with divide by zero to have undefine RT for both
          divde[.] and divdeu[.]
        * with negative dividend to cover -|divisor| < r <= 0 if
          the dividend is negative for divde[.]
        * normal case with proper dividend and divisor for both
          divde[.] and divdeu[.]

Reviewed-by: Sandipan Das <sandipan@linux.ibm.com>
Signed-off-by: Balamuruhan S <bala24@linux.ibm.com>
---
 arch/powerpc/lib/test_emulate_step.c | 164 +++++++++++++++++++++++++++++++++++
 1 file changed, 164 insertions(+)

diff --git a/arch/powerpc/lib/test_emulate_step.c b/arch/powerpc/lib/test_emulate_step.c
index 42347067739c..552b62a70e55 100644
--- a/arch/powerpc/lib/test_emulate_step.c
+++ b/arch/powerpc/lib/test_emulate_step.c
@@ -53,6 +53,14 @@
 					___PPC_RA(a) | ___PPC_RB(b))
 #define TEST_ADDC_DOT(t, a, b)	(PPC_INST_ADDC | ___PPC_RT(t) |		\
 					___PPC_RA(a) | ___PPC_RB(b) | 0x1)
+#define TEST_DIVDE(t, a, b)	(PPC_INST_DIVDE | ___PPC_RT(t) |	\
+					___PPC_RA(a) | ___PPC_RB(b))
+#define TEST_DIVDE_DOT(t, a, b)	(PPC_INST_DIVDE_DOT | ___PPC_RT(t) |	\
+					___PPC_RA(a) | ___PPC_RB(b))
+#define TEST_DIVDEU(t, a, b)	(PPC_INST_DIVDEU | ___PPC_RT(t) |	\
+					___PPC_RA(a) | ___PPC_RB(b))
+#define TEST_DIVDEU_DOT(t, a, b)(PPC_INST_DIVDEU_DOT | ___PPC_RT(t) |	\
+					___PPC_RA(a) | ___PPC_RB(b))
 
 #define MAX_SUBTESTS	16
 
@@ -837,6 +845,162 @@ static struct compute_test compute_tests[] = {
 				}
 			}
 		}
+	},
+	{
+		.mnemonic = "divde",
+		.subtests = {
+			{
+				.descr = "RA = LONG_MIN, RB = LONG_MIN",
+				.instr = TEST_DIVDE(20, 21, 22),
+				.regs = {
+					.gpr[21] = LONG_MIN,
+					.gpr[22] = LONG_MIN,
+				}
+			},
+			{
+				.descr = "RA = 1L, RB = 0",
+				.instr = TEST_DIVDE(20, 21, 22),
+				.flags = IGNORE_GPR(20),
+				.regs = {
+					.gpr[21] = 1L,
+					.gpr[22] = 0,
+				}
+			},
+			{
+				.descr = "RA = LONG_MIN, RB = LONG_MAX",
+				.instr = TEST_DIVDE(20, 21, 22),
+				.regs = {
+					.gpr[21] = LONG_MIN,
+					.gpr[22] = LONG_MAX,
+				}
+			}
+		}
+	},
+	{
+		.mnemonic = "divde.",
+		.subtests = {
+			{
+				.descr = "RA = LONG_MIN, RB = LONG_MIN",
+				.instr = TEST_DIVDE_DOT(20, 21, 22),
+				.regs = {
+					.gpr[21] = LONG_MIN,
+					.gpr[22] = LONG_MIN,
+				}
+			},
+			{
+				.descr = "RA = 1L, RB = 0",
+				.instr = TEST_DIVDE_DOT(20, 21, 22),
+				.flags = IGNORE_GPR(20),
+				.regs = {
+					.gpr[21] = 1L,
+					.gpr[22] = 0,
+				}
+			},
+			{
+				.descr = "RA = LONG_MIN, RB = LONG_MAX",
+				.instr = TEST_DIVDE_DOT(20, 21, 22),
+				.regs = {
+					.gpr[21] = LONG_MIN,
+					.gpr[22] = LONG_MAX,
+				}
+			}
+		}
+	},
+	{
+		.mnemonic = "divdeu",
+		.subtests = {
+			{
+				.descr = "RA = LONG_MIN, RB = LONG_MIN",
+				.instr = TEST_DIVDEU(20, 21, 22),
+				.flags = IGNORE_GPR(20),
+				.regs = {
+					.gpr[21] = LONG_MIN,
+					.gpr[22] = LONG_MIN,
+				}
+			},
+			{
+				.descr = "RA = 1L, RB = 0",
+				.instr = TEST_DIVDEU(20, 21, 22),
+				.flags = IGNORE_GPR(20),
+				.regs = {
+					.gpr[21] = 1L,
+					.gpr[22] = 0,
+				}
+			},
+			{
+				.descr = "RA = LONG_MIN, RB = LONG_MAX",
+				.instr = TEST_DIVDEU(20, 21, 22),
+				.regs = {
+					.gpr[21] = LONG_MIN,
+					.gpr[22] = LONG_MAX,
+				}
+			},
+			{
+				.descr = "RA = LONG_MAX - 1, RB = LONG_MAX",
+				.instr = TEST_DIVDEU_DOT(20, 21, 22),
+				.regs = {
+					.gpr[21] = LONG_MAX - 1,
+					.gpr[22] = LONG_MAX,
+				}
+			},
+			{
+				.descr = "RA = LONG_MIN + 1, RB = LONG_MIN",
+				.instr = TEST_DIVDEU_DOT(20, 21, 22),
+				.flags = IGNORE_GPR(20),
+				.regs = {
+					.gpr[21] = LONG_MIN + 1,
+					.gpr[22] = LONG_MIN,
+				}
+			}
+		}
+	},
+	{
+		.mnemonic = "divdeu.",
+		.subtests = {
+			{
+				.descr = "RA = LONG_MIN, RB = LONG_MIN",
+				.instr = TEST_DIVDEU_DOT(20, 21, 22),
+				.flags = IGNORE_GPR(20),
+				.regs = {
+					.gpr[21] = LONG_MIN,
+					.gpr[22] = LONG_MIN,
+				}
+			},
+			{
+				.descr = "RA = 1L, RB = 0",
+				.instr = TEST_DIVDEU_DOT(20, 21, 22),
+				.flags = IGNORE_GPR(20),
+				.regs = {
+					.gpr[21] = 1L,
+					.gpr[22] = 0,
+				}
+			},
+			{
+				.descr = "RA = LONG_MIN, RB = LONG_MAX",
+				.instr = TEST_DIVDEU_DOT(20, 21, 22),
+				.regs = {
+					.gpr[21] = LONG_MIN,
+					.gpr[22] = LONG_MAX,
+				}
+			},
+			{
+				.descr = "RA = LONG_MAX - 1, RB = LONG_MAX",
+				.instr = TEST_DIVDEU_DOT(20, 21, 22),
+				.regs = {
+					.gpr[21] = LONG_MAX - 1,
+					.gpr[22] = LONG_MAX,
+				}
+			},
+			{
+				.descr = "RA = LONG_MIN + 1, RB = LONG_MIN",
+				.instr = TEST_DIVDEU_DOT(20, 21, 22),
+				.flags = IGNORE_GPR(20),
+				.regs = {
+					.gpr[21] = LONG_MIN + 1,
+					.gpr[22] = LONG_MIN,
+				}
+			}
+		}
 	}
 };
 
-- 
2.14.5