[Qemu-devel] [RFC PATCH V1 2/2] target-microblaze: lwx/swx: first implementation

[Peter A. G. Crosthwaite]

Signed-off-by: Peter A. G. Crosthwaite <peter.crosthwa...@petalogix.com>
---
 target-microblaze/cpu.h       |    1 +
 target-microblaze/helper.c    |    2 +
 target-microblaze/translate.c |   51 ++++++++++++++++++++++++++++++++++++++--
 3 files changed, 51 insertions(+), 3 deletions(-)

diff --git a/target-microblaze/cpu.h b/target-microblaze/cpu.h
index 718d5bb..775a16d 100644
--- a/target-microblaze/cpu.h
+++ b/target-microblaze/cpu.h
@@ -250,6 +250,7 @@ struct CPUMBState {
 #define DRTE_FLAG      (1 << 17)
 #define DRTB_FLAG      (1 << 18)
 #define D_FLAG         (1 << 19)  /* Bit in ESR.  */
+#define R_FLAG      (1 << 24) /* Reservation Bit */
 /* TB dependent CPUMBState.  */
 #define IFLAGS_TB_MASK  (D_FLAG | IMM_FLAG | DRTI_FLAG | DRTE_FLAG | DRTB_FLAG)
     uint32_t iflags;
diff --git a/target-microblaze/helper.c b/target-microblaze/helper.c
index 2412a58..235f1be 100644
--- a/target-microblaze/helper.c
+++ b/target-microblaze/helper.c
@@ -29,6 +29,7 @@
 void do_interrupt (CPUMBState *env)
 {
     env->exception_index = -1;
+    env->iflags &= ~R_FLAG;
     env->regs[14] = env->sregs[SR_PC];
 }
 
@@ -116,6 +117,7 @@ void do_interrupt(CPUMBState *env)
     assert(!((env->iflags & D_FLAG) && (env->iflags & IMM_FLAG)));
     assert(!(env->iflags & (DRTI_FLAG | DRTE_FLAG | DRTB_FLAG)));
 /*    assert(env->sregs[SR_MSR] & (MSR_EE)); Only for HW exceptions.  */
+    env->iflags &= ~R_FLAG;
     switch (env->exception_index) {
         case EXCP_HW_EXCP:
             if (!(env->pvr.regs[0] & PVR0_USE_EXC_MASK)) {
diff --git a/target-microblaze/translate.c b/target-microblaze/translate.c
index a362938..9c1a0b5 100644
--- a/target-microblaze/translate.c
+++ b/target-microblaze/translate.c
@@ -948,12 +948,13 @@ static inline void dec_byteswap(DisasContext *dc, TCGv 
dst, TCGv src, int size)
 static void dec_load(DisasContext *dc)
 {
     TCGv t, *addr;
-    unsigned int size, rev = 0;
+    unsigned int size, rev = 0, ex = 0;
 
     size = 1 << (dc->opcode & 3);
 
     if (!dc->type_b) {
         rev = (dc->ir >> 9) & 1;
+        ex = (dc->ir >> 10) & 1;
     }
 
     if (size > 4 && (dc->tb_flags & MSR_EE_FLAG)
@@ -1019,6 +1020,17 @@ static void dec_load(DisasContext *dc)
         }
     }
 
+    /* lwx does not throw unaligned access errors, so force alignment */
+    if (ex) {
+        /* Force addr into the temp.  */
+        if (addr != &t) {
+            t = tcg_temp_new();
+            tcg_gen_mov_tl(t, *addr);
+            addr = &t;
+        }
+        tcg_gen_andi_tl(t, t, ~3);
+    }
+
     /* If we get a fault on a dslot, the jmpstate better be in sync.  */
     sync_jmpstate(dc);
 
@@ -1057,6 +1069,13 @@ static void dec_load(DisasContext *dc)
         }
     }
 
+    if (ex) { /* lwx */
+        /* no support for for AXI exlusive so always clear C */
+        TCGv_i32 zero = tcg_const_i32(0);
+        write_carry(dc, zero);
+        dc->tb_flags |= R_FLAG;
+    }
+
     if (addr == &t)
         tcg_temp_free(t);
 }
@@ -1078,12 +1097,14 @@ static void gen_store(DisasContext *dc, TCGv addr, TCGv 
val,
 
 static void dec_store(DisasContext *dc)
 {
-    TCGv t, *addr;
-    unsigned int size, rev = 0;
+    TCGv t, *addr, swx_carry = 0;
+    int swx_skip;
+    unsigned int size, rev = 0, ex = 0;
 
     size = 1 << (dc->opcode & 3);
     if (!dc->type_b) {
         rev = (dc->ir >> 9) & 1;
+        ex = (dc->ir >> 10) & 1;
     }
 
     if (size > 4 && (dc->tb_flags & MSR_EE_FLAG)
@@ -1099,6 +1120,26 @@ static void dec_store(DisasContext *dc)
     sync_jmpstate(dc);
     addr = compute_ldst_addr(dc, &t);
 
+    if (ex) { /* swx */
+        TCGv r_check = tcg_temp_new();
+        swx_carry = tcg_temp_new();
+        swx_skip = gen_new_label();
+
+        tcg_gen_andi_tl(r_check, env_iflags, R_FLAG);
+        tcg_gen_movi_tl(swx_carry, 1);
+        tcg_gen_brcondi_tl(TCG_COND_NE, r_check, R_FLAG, swx_skip);
+        tcg_gen_movi_tl(swx_carry, 0);
+
+        /* Force addr into the temp.  */
+        if (addr != &t) {
+            t = tcg_temp_new();
+            tcg_gen_mov_tl(t, *addr);
+            addr = &t;
+        }
+        /* swx does not throw unaligned access errors, so force alignment */
+        tcg_gen_andi_tl(t, t, ~3);
+    }
+
     if (rev && size != 4) {
         /* Endian reverse the address. t is addr.  */
         switch (size) {
@@ -1174,6 +1215,10 @@ static void dec_store(DisasContext *dc)
         gen_helper_memalign(*addr, tcg_const_tl(dc->rd),
                             tcg_const_tl(1), tcg_const_tl(size - 1));
     }
+    if (ex) {
+        gen_set_label(swx_skip);
+        write_carry(dc, swx_carry);
+    }
 
     if (addr == &t)
         tcg_temp_free(t);
-- 
1.7.3.2