[PATCH 14/20] target/arm: Convert CBZ, CBNZ to decodetree

[Peter Maydell]

Convert the compare-and-branch-immediate insns CBZ and CBNZ
to decodetree.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
 target/arm/tcg/a64.decode      |  6 ++++++
 target/arm/tcg/translate-a64.c | 26 ++++++--------------------
 2 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/target/arm/tcg/a64.decode b/target/arm/tcg/a64.decode
index d54c6522028..86220569e13 100644
--- a/target/arm/tcg/a64.decode
+++ b/target/arm/tcg/a64.decode
@@ -115,3 +115,9 @@ EXTR            . 00 100111 . 0 ..... ...... ..... ..... 
@extract_32
 
 B               0 00101 .......................... @branch
 BL              1 00101 .......................... @branch
+
+%imm19   5:s19 !function=times_4
+&cbz     rt imm sf nz
+@cbz            sf:1 ...... nz:1 ................... rt:5 &cbz imm=%imm19
+
+CBZ             . 011010 . ................... ..... @cbz
diff --git a/target/arm/tcg/translate-a64.c b/target/arm/tcg/translate-a64.c
index fe6b4a68288..5da551385bd 100644
--- a/target/arm/tcg/translate-a64.c
+++ b/target/arm/tcg/translate-a64.c
@@ -1334,33 +1334,22 @@ static bool trans_BL(DisasContext *s, arg_i *a)
     return true;
 }
 
-/* Compare and branch (immediate)
- *   31  30         25  24  23                  5 4      0
- * +----+-------------+----+---------------------+--------+
- * | sf | 0 1 1 0 1 0 | op |         imm19       |   Rt   |
- * +----+-------------+----+---------------------+--------+
- */
-static void disas_comp_b_imm(DisasContext *s, uint32_t insn)
+
+static bool trans_CBZ(DisasContext *s, arg_cbz *a)
 {
-    unsigned int sf, op, rt;
-    int64_t diff;
     DisasLabel match;
     TCGv_i64 tcg_cmp;
 
-    sf = extract32(insn, 31, 1);
-    op = extract32(insn, 24, 1); /* 0: CBZ; 1: CBNZ */
-    rt = extract32(insn, 0, 5);
-    diff = sextract32(insn, 5, 19) * 4;
-
-    tcg_cmp = read_cpu_reg(s, rt, sf);
+    tcg_cmp = read_cpu_reg(s, a->rt, a->sf);
     reset_btype(s);
 
     match = gen_disas_label(s);
-    tcg_gen_brcondi_i64(op ? TCG_COND_NE : TCG_COND_EQ,
+    tcg_gen_brcondi_i64(a->nz ? TCG_COND_NE : TCG_COND_EQ,
                         tcg_cmp, 0, match.label);
     gen_goto_tb(s, 0, 4);
     set_disas_label(s, match);
-    gen_goto_tb(s, 1, diff);
+    gen_goto_tb(s, 1, a->imm);
+    return true;
 }
 
 /* Test and branch (immediate)
@@ -2408,9 +2397,6 @@ static void disas_uncond_b_reg(DisasContext *s, uint32_t 
insn)
 static void disas_b_exc_sys(DisasContext *s, uint32_t insn)
 {
     switch (extract32(insn, 25, 7)) {
-    case 0x1a: case 0x5a: /* Compare & branch (immediate) */
-        disas_comp_b_imm(s, insn);
-        break;
     case 0x1b: case 0x5b: /* Test & branch (immediate) */
         disas_test_b_imm(s, insn);
         break;
-- 
2.34.1