[Qemu-devel] [PATCH][SPARC] Fix handling of conditional branches in delay slot of a conditional branch

[Artyom Tarasenko]

Check whether dc->npc is dynamic before using its value for branch.

Signed-off-by: Artyom Tarasenko <address@hidden>
---
Particaluary the patch fixes handling of the constructions like

0x13e26c0:  brz,pn   %o0, 0x13e26e4
0x13e26c4:  brlez,pn   %o1, 0x13e26e4

present in NetBSD-5.1

 target-sparc/translate.c |   30 +++++++++++++++++++++---------
 1 files changed, 21 insertions(+), 9 deletions(-)

diff --git a/target-sparc/translate.c b/target-sparc/translate.c
index 958fbc5..dee67b3 100644
--- a/target-sparc/translate.c
+++ b/target-sparc/translate.c
@@ -1286,7 +1286,6 @@ static inline void gen_cond_reg(TCGv r_dst, int cond, 
TCGv r_src)
 }
 #endif
 
-/* XXX: potentially incorrect if dynamic npc */
 static void do_branch(DisasContext *dc, int32_t offset, uint32_t insn, int cc,
                       TCGv r_cond)
 {
@@ -1321,13 +1320,17 @@ static void do_branch(DisasContext *dc, int32_t offset, 
uint32_t insn, int cc,
         } else {
             dc->pc = dc->npc;
             dc->jump_pc[0] = target;
-            dc->jump_pc[1] = dc->npc + 4;
-            dc->npc = JUMP_PC;
+            if (unlikely(dc->npc == DYNAMIC_PC)) {
+                dc->jump_pc[1] = DYNAMIC_PC;
+                tcg_gen_addi_tl(cpu_pc, cpu_npc, 4);
+            } else {
+                dc->jump_pc[1] = dc->npc + 4;
+                dc->npc = JUMP_PC;
+            }
         }
     }
 }
 
-/* XXX: potentially incorrect if dynamic npc */
 static void do_fbranch(DisasContext *dc, int32_t offset, uint32_t insn, int cc,
                       TCGv r_cond)
 {
@@ -1362,14 +1365,18 @@ static void do_fbranch(DisasContext *dc, int32_t 
offset, uint32_t insn, int cc,
         } else {
             dc->pc = dc->npc;
             dc->jump_pc[0] = target;
-            dc->jump_pc[1] = dc->npc + 4;
-            dc->npc = JUMP_PC;
+            if (unlikely(dc->npc == DYNAMIC_PC)) {
+                dc->jump_pc[1] = DYNAMIC_PC;
+                tcg_gen_addi_tl(cpu_pc, cpu_npc, 4);
+            } else {
+                dc->jump_pc[1] = dc->npc + 4;
+                dc->npc = JUMP_PC;
+            }
         }
     }
 }
 
 #ifdef TARGET_SPARC64
-/* XXX: potentially incorrect if dynamic npc */
 static void do_branch_reg(DisasContext *dc, int32_t offset, uint32_t insn,
                           TCGv r_cond, TCGv r_reg)
 {
@@ -1384,8 +1391,13 @@ static void do_branch_reg(DisasContext *dc, int32_t 
offset, uint32_t insn,
     } else {
         dc->pc = dc->npc;
         dc->jump_pc[0] = target;
-        dc->jump_pc[1] = dc->npc + 4;
-        dc->npc = JUMP_PC;
+        if (unlikely(dc->npc == DYNAMIC_PC)) {
+            dc->jump_pc[1] = DYNAMIC_PC;
+            tcg_gen_addi_tl(cpu_pc, cpu_npc, 4);
+        } else {
+            dc->jump_pc[1] = dc->npc + 4;
+            dc->npc = JUMP_PC;
+        }
     }
 }
 
-- 
1.7.3.4