[Qemu-devel] [PATCH v1 03/41] s390x/tcg: Implement VECTOR ADD COMPUTE CARRY

[David Hildenbrand <david@redhat.com>]

Only 64 bit handling is really easy. 128 bit handling is performed
via an ool handler, introducing s390_vec_add() that will be reused later.

8/16/32 bit handling is black magic inspired by gen_addv_mask(). If
there is every a bug detected in there, throw it away and simply use
ool helpers for 8/16 bit handling and something like 64 bit handling for
32 bit handling.

Signed-off-by: David Hildenbrand <david@redhat.com>
---
 target/s390x/Makefile.objs      |  2 +-
 target/s390x/helper.h           |  3 ++
 target/s390x/insn-data.def      |  2 +
 target/s390x/translate_vx.inc.c | 74 +++++++++++++++++++++++++++++++++
 target/s390x/vec_int_helper.c   | 47 +++++++++++++++++++++
 5 files changed, 127 insertions(+), 1 deletion(-)
 create mode 100644 target/s390x/vec_int_helper.c

diff --git a/target/s390x/Makefile.objs b/target/s390x/Makefile.objs
index 68eeee3d2f..993ac93ed6 100644
--- a/target/s390x/Makefile.objs
+++ b/target/s390x/Makefile.objs
@@ -1,7 +1,7 @@
 obj-y += cpu.o cpu_models.o cpu_features.o gdbstub.o interrupt.o helper.o
 obj-$(CONFIG_TCG) += translate.o cc_helper.o excp_helper.o fpu_helper.o
 obj-$(CONFIG_TCG) += int_helper.o mem_helper.o misc_helper.o crypto_helper.o
-obj-$(CONFIG_TCG) += vec_helper.o
+obj-$(CONFIG_TCG) += vec_helper.o vec_int_helper.o
 obj-$(CONFIG_SOFTMMU) += machine.o ioinst.o arch_dump.o mmu_helper.o diag.o
 obj-$(CONFIG_SOFTMMU) += sigp.o
 obj-$(CONFIG_KVM) += kvm.o
diff --git a/target/s390x/helper.h b/target/s390x/helper.h
index 0b494a2fd2..2c1b223248 100644
--- a/target/s390x/helper.h
+++ b/target/s390x/helper.h
@@ -145,6 +145,9 @@ DEF_HELPER_5(gvec_vpkls_cc64, void, ptr, cptr, cptr, env, i32)
 DEF_HELPER_FLAGS_5(gvec_vperm, TCG_CALL_NO_RWG, void, ptr, cptr, cptr, cptr, i32)
 DEF_HELPER_FLAGS_4(vstl, TCG_CALL_NO_WG, void, env, cptr, i64, i64)
 
+/* === Vector Integer Instructions === */
+DEF_HELPER_FLAGS_4(gvec_vacc128, TCG_CALL_NO_RWG, void, ptr, cptr, cptr, i32)
+
 #ifndef CONFIG_USER_ONLY
 DEF_HELPER_3(servc, i32, env, i64, i64)
 DEF_HELPER_4(diag, void, env, i32, i32, i32)
diff --git a/target/s390x/insn-data.def b/target/s390x/insn-data.def
index 74a0ccc770..f0e62b9aa8 100644
--- a/target/s390x/insn-data.def
+++ b/target/s390x/insn-data.def
@@ -1058,6 +1058,8 @@
 
 /* VECTOR ADD */
     F(0xe7f3, VA,      VRR_c, V,   0, 0, 0, 0, va, 0, IF_VEC)
+/* VECTOR ADD COMPUTE CARRY */
+    F(0xe7f1, VACC,    VRR_c, V,   0, 0, 0, 0, vacc, 0, IF_VEC)
 
 #ifndef CONFIG_USER_ONLY
 /* COMPARE AND SWAP AND PURGE */
diff --git a/target/s390x/translate_vx.inc.c b/target/s390x/translate_vx.inc.c
index 2f84ea0511..c3bc47f1a9 100644
--- a/target/s390x/translate_vx.inc.c
+++ b/target/s390x/translate_vx.inc.c
@@ -136,6 +136,9 @@ static void get_vec_element_ptr_i64(TCGv_ptr ptr, uint8_t reg, TCGv_i64 enr,
     tcg_temp_free_i64(tmp);
 }
 
+#define gen_gvec_3(v1, v2, v3, gen) \
+    tcg_gen_gvec_3(vec_full_reg_offset(v1), vec_full_reg_offset(v2), \
+                   vec_full_reg_offset(v3), 16, 16, gen)
 #define gen_gvec_3_ool(v1, v2, v3, data, fn) \
     tcg_gen_gvec_3_ool(vec_full_reg_offset(v1), vec_full_reg_offset(v2), \
                        vec_full_reg_offset(v3), 16, 16, data, fn)
@@ -985,3 +988,74 @@ static DisasJumpType op_va(DisasContext *s, DisasOps *o)
                   get_field(s->fields, v3));
     return DISAS_NEXT;
 }
+
+static void gen_acc(TCGv_i64 d, TCGv_i64 a, TCGv_i64 b, uint8_t es)
+{
+    const uint8_t msb_bit_nr = NUM_VEC_ELEMENT_BITS(es) - 1;
+    TCGv_i64 msb_mask = tcg_const_i64(dup_const(es, 1ull << msb_bit_nr));
+    TCGv_i64 t1 = tcg_temp_new_i64();
+    TCGv_i64 t2 = tcg_temp_new_i64();
+    TCGv_i64 t3 = tcg_temp_new_i64();
+
+    /* Calculate the carry into the MSB, ignoring the old MSBs */
+    tcg_gen_andc_i64(t1, a, msb_mask);
+    tcg_gen_andc_i64(t2, b, msb_mask);
+    tcg_gen_add_i64(t1, t1, t2);
+    /* Calculate the MSB without any carry into it */
+    tcg_gen_xor_i64(t3, a, b);
+    /* Calculate the carry out of the MSB in the MSB bit position */
+    tcg_gen_and_i64(d, a, b);
+    tcg_gen_and_i64(t1, t1, t3);
+    tcg_gen_or_i64(d, d, t1);
+    /* Isolate and shift the carry into position */
+    tcg_gen_and_i64(d, d, msb_mask);
+    tcg_gen_shri_i64(d, d, msb_bit_nr);
+
+    tcg_temp_free_i64(t1);
+    tcg_temp_free_i64(t2);
+    tcg_temp_free_i64(t3);
+}
+
+static void gen_acc8_i64(TCGv_i64 d, TCGv_i64 a, TCGv_i64 b)
+{
+    gen_acc(d, a, b, ES_8);
+}
+
+static void gen_acc16_i64(TCGv_i64 d, TCGv_i64 a, TCGv_i64 b)
+{
+    gen_acc(d, a, b, ES_16);
+}
+
+static void gen_acc32_i64(TCGv_i64 d, TCGv_i64 a, TCGv_i64 b)
+{
+    gen_acc(d, a, b, ES_32);
+}
+
+static void gen_acc_i64(TCGv_i64 d, TCGv_i64 a, TCGv_i64 b)
+{
+    TCGv_i64 t = tcg_temp_new_i64();
+
+    tcg_gen_add_i64(t, a, b);
+    tcg_gen_setcond_i64(TCG_COND_LTU, d, t, b);
+    tcg_temp_free_i64(t);
+}
+
+static DisasJumpType op_vacc(DisasContext *s, DisasOps *o)
+{
+    const uint8_t es = get_field(s->fields, m4);
+    static const GVecGen3 g[5] = {
+        { .fni8 = gen_acc8_i64, },
+        { .fni8 = gen_acc16_i64, },
+        { .fni8 = gen_acc32_i64, },
+        { .fni8 = gen_acc_i64, },
+        { .fno = gen_helper_gvec_vacc128, },
+    };
+
+    if (es > ES_128) {
+        gen_program_exception(s, PGM_SPECIFICATION);
+        return DISAS_NORETURN;
+    }
+    gen_gvec_3(get_field(s->fields, v1), get_field(s->fields, v2),
+               get_field(s->fields, v3), &g[es]);
+    return DISAS_NEXT;
+}
diff --git a/target/s390x/vec_int_helper.c b/target/s390x/vec_int_helper.c
new file mode 100644
index 0000000000..0b232571bc
--- /dev/null
+++ b/target/s390x/vec_int_helper.c
@@ -0,0 +1,47 @@
+/*
+ * QEMU TCG support -- s390x vector integer instruction support
+ *
+ * Copyright (C) 2019 Red Hat Inc
+ *
+ * Authors:
+ *   David Hildenbrand <david@redhat.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ */
+#include "qemu/osdep.h"
+#include "qemu-common.h"
+#include "cpu.h"
+#include "vec.h"
+#include "exec/helper-proto.h"
+
+/*
+ * Add two 128 bit vectors, returning the carry.
+ */
+static bool s390_vec_add(S390Vector *d, const S390Vector *a,
+                         const S390Vector *b)
+{
+    bool low_carry = false, high_carry = false;
+
+    if (a->doubleword[0] + b->doubleword[0] < a->doubleword[0]) {
+        high_carry = true;
+    }
+    if (a->doubleword[1] + b->doubleword[1] < a->doubleword[1]) {
+        low_carry = true;
+        if (a->doubleword[0] == b->doubleword[0]) {
+            high_carry = true;
+        }
+    }
+    d->doubleword[0] = a->doubleword[0] + b->doubleword[0] + low_carry;
+    d->doubleword[1] = a->doubleword[1] + b->doubleword[1];
+    return high_carry;
+}
+
+void HELPER(gvec_vacc128)(void *v1, const void *v2, const void *v3,
+                          uint32_t desc)
+{
+    S390Vector tmp, *dst = v1;
+
+    dst->doubleword[0] = 0;
+    dst->doubleword[1] = s390_vec_add(&tmp, v2, v3);
+}
-- 
2.20.1