[PATCH v4 15/21] 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>
Signed-off-by: XiaoJuan Yang <yangxiaojuan@loongson.cn>
---
 target/loongarch/insn_trans/trans_branch.c | 84 ++++++++++++++++++++++++++++++
 target/loongarch/insns.decode              | 30 +++++++++++
 target/loongarch/translate.c               |  1 +
 3 files changed, 115 insertions(+)
 create mode 100644 target/loongarch/insn_trans/trans_branch.c

diff --git a/target/loongarch/insn_trans/trans_branch.c b/target/loongarch/insn_trans/trans_branch.c
new file mode 100644
index 0000000..acf1966
--- /dev/null
+++ b/target/loongarch/insn_trans/trans_branch.c
@@ -0,0 +1,84 @@
+/*
+ * LoongArch translate functions
+ *
+ * Copyright (c) 2021 Loongson Technology Corporation Limited
+ *
+ * SPDX-License-Identifier: LGPL-2.1+
+ */
+
+static bool trans_b(DisasContext *ctx, arg_b *a)
+{
+    gen_goto_tb(ctx, 0, ctx->base.pc_next + (a->offs << 2));
+    ctx->base.is_jmp = DISAS_NORETURN;
+    return true;
+}
+
+static bool trans_bl(DisasContext *ctx, arg_bl *a)
+{
+    tcg_gen_movi_tl(cpu_gpr[1], ctx->base.pc_next + 4);
+    gen_goto_tb(ctx, 0, ctx->base.pc_next + (a->offs << 2));
+    ctx->base.is_jmp = DISAS_NORETURN;
+    return true;
+}
+
+static bool trans_jirl(DisasContext *ctx, arg_jirl *a)
+{
+    TCGv dest = gpr_dst(ctx, a->rd);
+    TCGv src1 = gpr_src(ctx, a->rj, EXT_NONE);
+
+    tcg_gen_addi_tl(cpu_pc, src1, (a->offs16) << 2);
+    tcg_gen_movi_tl(dest, ctx->base.pc_next + 4);
+    tcg_gen_lookup_and_goto_ptr();
+    ctx->base.is_jmp = DISAS_NORETURN;
+    return true;
+}
+
+static void gen_bc(DisasContext *ctx, TCGv src1, TCGv src2,
+                   target_long offs, TCGCond cond)
+{
+    TCGLabel *l = gen_new_label();
+    tcg_gen_brcond_tl(cond, src1, src2, l);
+    gen_goto_tb(ctx, 1, ctx->base.pc_next + 4);
+    gen_set_label(l);
+    gen_goto_tb(ctx, 0, ctx->base.pc_next + offs);
+    ctx->base.is_jmp = DISAS_NORETURN;
+}
+
+static bool gen_r2_bc(DisasContext *ctx, arg_fmt_rjrdoffs16 *a, TCGCond cond)
+{
+    TCGv src1 = gpr_src(ctx, a->rj, EXT_NONE);
+    TCGv src2 = gpr_src(ctx, a->rd, EXT_NONE);
+
+    gen_bc(ctx, src1, src2, (a->offs16 << 2), cond);
+    return true;
+}
+
+static bool gen_rz_bc(DisasContext *ctx, arg_fmt_rjoffs21 *a, TCGCond cond)
+{
+    TCGv src1 = gpr_src(ctx, a->rj, EXT_NONE);
+    TCGv src2 = tcg_constant_tl(0);
+
+    gen_bc(ctx, src1, src2, (a->offs21 << 2), cond);
+    return true;
+}
+static bool gen_cz_bc(DisasContext *ctx, arg_fmt_cjoffs21 *a, TCGCond cond)
+{
+    TCGv src1 = tcg_temp_new();
+    TCGv src2 = tcg_constant_tl(0);
+
+    tcg_gen_ld8u_tl(src1, cpu_env,
+                    offsetof(CPULoongArchState, cf[a->cj & 0x7]));
+    gen_bc(ctx, src1, src2, (a->offs21 << 2), cond);
+    return true;
+}
+
+TRANS(beq, gen_r2_bc, TCG_COND_EQ)
+TRANS(bne, gen_r2_bc, TCG_COND_NE)
+TRANS(blt, gen_r2_bc, TCG_COND_LT)
+TRANS(bge, gen_r2_bc, TCG_COND_GE)
+TRANS(bltu, gen_r2_bc, TCG_COND_LTU)
+TRANS(bgeu, gen_r2_bc, TCG_COND_GEU)
+TRANS(beqz, gen_rz_bc, TCG_COND_EQ)
+TRANS(bnez, gen_rz_bc, TCG_COND_NE)
+TRANS(bceqz, gen_cz_bc, TCG_COND_EQ)
+TRANS(bcnez, gen_cz_bc, TCG_COND_NE)
diff --git a/target/loongarch/insns.decode b/target/loongarch/insns.decode
index ea776c2..077063e 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
@@ -74,6 +77,11 @@
 &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
@@ -110,6 +118,11 @@
 @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
@@ -448,3 +461,20 @@ 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/translate.c b/target/loongarch/translate.c
index 7c2c80b..6bd3ce1 100644
--- a/target/loongarch/translate.c
+++ b/target/loongarch/translate.c
@@ -210,6 +210,7 @@ static bool gen_f2(DisasContext *ctx, arg_fmt_fdfj *a,
 #include "insn_trans/trans_fcnv.c"
 #include "insn_trans/trans_fmov.c"
 #include "insn_trans/trans_fmemory.c"
+#include "insn_trans/trans_branch.c"
 
 static void loongarch_tr_translate_insn(DisasContextBase *dcbase, CPUState *cs)
 {
-- 
1.8.3.1