[PATCH 18/20] target/loongarch: Add branch instruction translation

[Song Gao <gaosong@loongson.cn>]

This patch implement branch instruction translation.

This includes:
- BEQ, BNE, BLT[U], BGE[U]
- BEQZ, BNEZ
- B
- BL
- JIRL
- BCEQZ, BCNEZ

Signed-off-by: Song Gao <gaosong@loongson.cn>
---
 target/loongarch/insns.decode |  30 ++++++++++++
 target/loongarch/instmap.h    |  13 +++++
 target/loongarch/trans.inc.c  | 110 ++++++++++++++++++++++++++++++++++++++++++
 target/loongarch/translate.c  |  96 ++++++++++++++++++++++++++++++++++++
 4 files changed, 249 insertions(+)

diff --git a/target/loongarch/insns.decode b/target/loongarch/insns.decode
index cff0955..37fd8e5 100644
--- a/target/loongarch/insns.decode
+++ b/target/loongarch/insns.decode
@@ -38,6 +38,9 @@
 %ca      15:3
 %fcsrd   0:5
 %fcsrs   5:5
+%offs21  0:s5 10:16
+%offs16  10:s16
+%offs    0:s10 10:16
 
 #
 # Argument sets
@@ -75,6 +78,11 @@
 &fmt_rdcj           rd cj
 &fmt_fdrjrk         fd rj rk
 &fmt_fdrjsi12       fd rj si12
+&fmt_rjoffs21       rj offs21
+&fmt_cjoffs21       cj offs21
+&fmt_rdrjoffs16     rd rj offs16
+&fmt_offs           offs
+&fmt_rjrdoffs16     rj rd offs16
 
 #
 # Formats
@@ -112,6 +120,11 @@
 @fmt_rdcj            .... ........ ..... ..... .. ... .....   &fmt_rdcj           %rd %cj
 @fmt_fdrjrk          .... ........ ..... ..... ..... .....    &fmt_fdrjrk         %fd %rj %rk
 @fmt_fdrjsi12        .... ...... ............ ..... .....     &fmt_fdrjsi12       %fd %rj %si12
+@fmt_rjoffs21        .... .. ................ ..... .....     &fmt_rjoffs21       %rj %offs21
+@fmt_cjoffs21        .... .. ................ .. ... .....    &fmt_cjoffs21       %cj %offs21
+@fmt_rdrjoffs16      .... .. ................ ..... .....     &fmt_rdrjoffs16     %rd %rj %offs16
+@fmt_offs            .... .. ..........................       &fmt_offs           %offs
+@fmt_rjrdoffs16      .... .. ................ ..... .....     &fmt_rjrdoffs16     %rj %rd %offs16
 
 #
 # Fixed point arithmetic operation instruction
@@ -451,3 +464,20 @@ fstgt_s          0011 10000111 01100 ..... ..... .....    @fmt_fdrjrk
 fstgt_d          0011 10000111 01101 ..... ..... .....    @fmt_fdrjrk
 fstle_s          0011 10000111 01110 ..... ..... .....    @fmt_fdrjrk
 fstle_d          0011 10000111 01111 ..... ..... .....    @fmt_fdrjrk
+
+#
+# Branch instructions
+#
+beqz             0100 00 ................ ..... .....     @fmt_rjoffs21
+bnez             0100 01 ................ ..... .....     @fmt_rjoffs21
+bceqz            0100 10 ................ 00 ... .....    @fmt_cjoffs21
+bcnez            0100 10 ................ 01 ... .....    @fmt_cjoffs21
+jirl             0100 11 ................ ..... .....     @fmt_rdrjoffs16
+b                0101 00 ..........................       @fmt_offs
+bl               0101 01 ..........................       @fmt_offs
+beq              0101 10 ................ ..... .....     @fmt_rjrdoffs16
+bne              0101 11 ................ ..... .....     @fmt_rjrdoffs16
+blt              0110 00 ................ ..... .....     @fmt_rjrdoffs16
+bge              0110 01 ................ ..... .....     @fmt_rjrdoffs16
+bltu             0110 10 ................ ..... .....     @fmt_rjrdoffs16
+bgeu             0110 11 ................ ..... .....     @fmt_rjrdoffs16
diff --git a/target/loongarch/instmap.h b/target/loongarch/instmap.h
index eb8e354..0e703c9 100644
--- a/target/loongarch/instmap.h
+++ b/target/loongarch/instmap.h
@@ -184,4 +184,17 @@ enum {
     LA_OPC_STPTR_D   = (0x27 << 24)
 };
 
+/* Branch opcodes */
+enum {
+    LA_OPC_BEQZ      = (0x10 << 26),
+    LA_OPC_BNEZ      = (0x11 << 26),
+    LA_OPC_B         = (0x14 << 26),
+    LA_OPC_BEQ       = (0x16 << 26),
+    LA_OPC_BNE       = (0x17 << 26),
+    LA_OPC_BLT       = (0x18 << 26),
+    LA_OPC_BGE       = (0x19 << 26),
+    LA_OPC_BLTU      = (0x1A << 26),
+    LA_OPC_BGEU      = (0x1B << 26)
+};
+
 #endif
diff --git a/target/loongarch/trans.inc.c b/target/loongarch/trans.inc.c
index d95101b..782f26c 100644
--- a/target/loongarch/trans.inc.c
+++ b/target/loongarch/trans.inc.c
@@ -2314,3 +2314,113 @@ static bool trans_fstle_d(DisasContext *ctx, arg_fstle_d *a)
     gen_loongarch_fldst_extra(ctx, LA_OPC_FSTLE_D, 0, a->fd, a->rj, a->rk);
     return true;
 }
+
+/* Branch Instructions translation */
+static bool trans_beqz(DisasContext *ctx, arg_beqz *a)
+{
+    gen_loongarch_jump(ctx, LA_OPC_BEQZ, 4, a->rj, 0, a->offs21 << 2);
+    return true;
+}
+
+static bool trans_bnez(DisasContext *ctx, arg_bnez *a)
+{
+    gen_loongarch_jump(ctx, LA_OPC_BNEZ, 4, a->rj, 0, a->offs21 << 2);
+    return true;
+}
+
+static bool trans_bceqz(DisasContext *ctx, arg_bceqz *a)
+{
+    TCGv_i32 cj = tcg_const_i32(a->cj);
+    TCGv v0 = tcg_temp_new();
+    TCGv v1 = tcg_const_i64(0);
+
+    gen_helper_movcf2reg(v0, cpu_env, cj);
+    tcg_gen_setcond_tl(TCG_COND_EQ, bcond, v0, v1);
+    ctx->hflags |= LOONGARCH_HFLAG_BC;
+    ctx->btarget = ctx->base.pc_next + (a->offs21 << 2);
+
+    tcg_temp_free_i32(cj);
+    tcg_temp_free(v0);
+    tcg_temp_free(v1);
+    return true;
+}
+
+static bool trans_bcnez(DisasContext *ctx, arg_bcnez *a)
+{
+    TCGv_i32 cj = tcg_const_i32(a->cj);
+    TCGv v0 = tcg_temp_new();
+    TCGv v1 = tcg_const_i64(0);
+
+    gen_helper_movcf2reg(v0, cpu_env, cj);
+    tcg_gen_setcond_tl(TCG_COND_NE, bcond, v0, v1);
+    ctx->hflags |= LOONGARCH_HFLAG_BC;
+    ctx->btarget = ctx->base.pc_next + (a->offs21 << 2);
+
+    tcg_temp_free_i32(cj);
+    tcg_temp_free(v0);
+    tcg_temp_free(v1);
+    return true;
+}
+
+static bool trans_b(DisasContext *ctx, arg_b *a)
+{
+    gen_loongarch_jump(ctx, LA_OPC_B, 4, 0, 0, a->offs << 2);
+    return true;
+}
+
+static bool trans_bl(DisasContext *ctx, arg_bl *a)
+{
+    ctx->btarget = ctx->base.pc_next + (a->offs << 2);
+    tcg_gen_movi_tl(cpu_gpr[1], ctx->base.pc_next + 4);
+    ctx->hflags |= LOONGARCH_HFLAG_B;
+    gen_branch(ctx, 4);
+    return true;
+}
+
+static bool trans_blt(DisasContext *ctx, arg_blt *a)
+{
+    gen_loongarch_jump(ctx, LA_OPC_BLT, 4, a->rj, a->rd, a->offs16 << 2);
+    return true;
+}
+
+static bool trans_bge(DisasContext *ctx, arg_bge *a)
+{
+    gen_loongarch_jump(ctx, LA_OPC_BGE, 4, a->rj, a->rd, a->offs16 << 2);
+    return true;
+}
+
+static bool trans_bltu(DisasContext *ctx, arg_bltu *a)
+{
+    gen_loongarch_jump(ctx, LA_OPC_BLTU, 4, a->rj, a->rd, a->offs16 << 2);
+    return true;
+}
+
+static bool trans_bgeu(DisasContext *ctx, arg_bgeu *a)
+{
+    gen_loongarch_jump(ctx, LA_OPC_BGEU, 4, a->rj, a->rd, a->offs16 << 2);
+    return true;
+}
+
+static bool trans_beq(DisasContext *ctx, arg_beq *a)
+{
+    gen_loongarch_jump(ctx, LA_OPC_BEQ, 4, a->rj, a->rd, a->offs16 << 2);
+    return true;
+}
+
+static bool trans_bne(DisasContext *ctx, arg_bne *a)
+{
+    gen_loongarch_jump(ctx, LA_OPC_BNE, 4, a->rj, a->rd, a->offs16 << 2);
+    return true;
+}
+
+static bool trans_jirl(DisasContext *ctx, arg_jirl *a)
+{
+    gen_base_offset_addr(ctx, btarget, a->rj, a->offs16 << 2);
+    if (a->rd != 0) {
+        tcg_gen_movi_tl(cpu_gpr[a->rd], ctx->base.pc_next + 4);
+    }
+    ctx->hflags |= LOONGARCH_HFLAG_BR;
+    gen_branch(ctx, 4);
+
+    return true;
+}
diff --git a/target/loongarch/translate.c b/target/loongarch/translate.c
index c1d89d8..9338f7f 100644
--- a/target/loongarch/translate.c
+++ b/target/loongarch/translate.c
@@ -2263,6 +2263,102 @@ static void gen_loongarch_fldst_extra(DisasContext *ctx, uint32_t opc,
     tcg_temp_free(t0);
 }
 
+static void gen_loongarch_jump(DisasContext *ctx, uint32_t opc,
+                               int insn_bytes,
+                               int rj, int rd, int32_t offset)
+{
+    target_ulong btgt = -1;
+    int bcond_flag = 0;
+    TCGv t0 = tcg_temp_new();
+    TCGv t1 = tcg_temp_new();
+
+    if (ctx->hflags & LOONGARCH_HFLAG_BMASK) {
+        generate_exception_end(ctx, EXCP_INE);
+        goto out;
+    }
+
+    /* Load needed operands */
+    switch (opc) {
+    case LA_OPC_BLT:
+    case LA_OPC_BGE:
+    case LA_OPC_BLTU:
+    case LA_OPC_BGEU:
+        gen_load_gpr(t0, rj);
+        gen_load_gpr(t1, rd);
+        bcond_flag = 1;
+        btgt = ctx->base.pc_next + offset;
+        break;
+    case LA_OPC_BEQZ:
+    case LA_OPC_B:
+    case LA_OPC_BEQ:
+    case LA_OPC_BNEZ:
+    case LA_OPC_BNE:
+        /* Compare two registers */
+        if (rj != rd) {
+            gen_load_gpr(t0, rj);
+            gen_load_gpr(t1, rd);
+            bcond_flag = 1;
+        }
+        btgt = ctx->base.pc_next + offset;
+        break;
+    default:
+        generate_exception_end(ctx, EXCP_INE);
+        goto out;
+    }
+    if (bcond_flag == 0) {
+        /* No condition to be computed */
+        switch (opc) {
+        case LA_OPC_BEQZ:
+        case LA_OPC_B:
+        case LA_OPC_BEQ:
+            ctx->hflags |= LOONGARCH_HFLAG_B;
+            break;
+        case LA_OPC_BNEZ:
+        case LA_OPC_BNE:
+            /* Treat as NOP. */
+            goto out;
+        default:
+            generate_exception_end(ctx, EXCP_INE);
+            goto out;
+        }
+    } else {
+        switch (opc) {
+        case LA_OPC_BLT:
+            tcg_gen_setcond_tl(TCG_COND_LT, bcond, t0, t1);
+            goto not_likely;
+        case LA_OPC_BGE:
+            tcg_gen_setcond_tl(TCG_COND_GE, bcond, t0, t1);
+            goto not_likely;
+        case LA_OPC_BLTU:
+            tcg_gen_setcond_tl(TCG_COND_LTU, bcond, t0, t1);
+            goto not_likely;
+        case LA_OPC_BGEU:
+            tcg_gen_setcond_tl(TCG_COND_GEU, bcond, t0, t1);
+            goto not_likely;
+        case LA_OPC_BEQZ:
+        case LA_OPC_B:
+        case LA_OPC_BEQ:
+            tcg_gen_setcond_tl(TCG_COND_EQ, bcond, t0, t1);
+            goto not_likely;
+        case LA_OPC_BNEZ:
+        case LA_OPC_BNE:
+            tcg_gen_setcond_tl(TCG_COND_NE, bcond, t0, t1);
+            goto not_likely;
+        not_likely:
+            ctx->hflags |= LOONGARCH_HFLAG_BC;
+            break;
+        default:
+            generate_exception_end(ctx, EXCP_INE);
+            goto out;
+        }
+    }
+    ctx->btarget = btgt;
+
+ out:
+    tcg_temp_free(t0);
+    tcg_temp_free(t1);
+}
+
 static void loongarch_tr_tb_start(DisasContextBase *dcbase, CPUState *cs)
 {
 }
-- 
1.8.3.1