[Qemu-devel] [PATCH 1/2] target-xtensa: implement depbits instruction

[Max Filippov]

This option provides an instruction for depositing a bit field from the
least significant position of one register to an arbitrary position in
another register.

Signed-off-by: Max Filippov <address@hidden>
---
 target-xtensa/cpu.h          |  1 +
 target-xtensa/overlay_tool.h |  5 +++++
 target-xtensa/translate.c    | 20 ++++++++++++++++++++
 3 files changed, 26 insertions(+)

diff --git a/target-xtensa/cpu.h b/target-xtensa/cpu.h
index 96bfc82..a45cb39 100644
--- a/target-xtensa/cpu.h
+++ b/target-xtensa/cpu.h
@@ -65,6 +65,7 @@ enum {
     XTENSA_OPTION_MP_SYNCHRO,
     XTENSA_OPTION_CONDITIONAL_STORE,
     XTENSA_OPTION_ATOMCTL,
+    XTENSA_OPTION_DEPBITS,
 
     /* Interrupts and exceptions */
     XTENSA_OPTION_EXCEPTION,
diff --git a/target-xtensa/overlay_tool.h b/target-xtensa/overlay_tool.h
index eda03aa..e8a7fda 100644
--- a/target-xtensa/overlay_tool.h
+++ b/target-xtensa/overlay_tool.h
@@ -30,6 +30,10 @@
     { .targno = (no), .type = (typ), .group = (grp), .size = (sz) },
 #define XTREG_END { .targno = -1 },
 
+#ifndef XCHAL_HAVE_DEPBITS
+#define XCHAL_HAVE_DEPBITS 0
+#endif
+
 #ifndef XCHAL_HAVE_DIV32
 #define XCHAL_HAVE_DIV32 0
 #endif
@@ -69,6 +73,7 @@
     XCHAL_OPTION(XCHAL_HAVE_S32C1I, XTENSA_OPTION_CONDITIONAL_STORE) | \
     XCHAL_OPTION(XCHAL_HAVE_S32C1I && XCHAL_HW_MIN_VERSION >= 230000, \
         XTENSA_OPTION_ATOMCTL) | \
+    XCHAL_OPTION(XCHAL_HAVE_DEPBITS, XTENSA_OPTION_DEPBITS) | \
     /* Interrupts and exceptions */ \
     XCHAL_OPTION(XCHAL_HAVE_EXCEPTIONS, XTENSA_OPTION_EXCEPTION) | \
     XCHAL_OPTION(XCHAL_HAVE_VECBASE, XTENSA_OPTION_RELOCATABLE_VECTOR) | \
diff --git a/target-xtensa/translate.c b/target-xtensa/translate.c
index f2118c2..cd2148e 100644
--- a/target-xtensa/translate.c
+++ b/target-xtensa/translate.c
@@ -1970,6 +1970,16 @@ static void disas_xtensa_insn(CPUXtensaState *env, 
DisasContext *dc)
             break;
 
         case 10: /*FP0*/
+            /*DEPBITS*/
+            if (option_enabled(dc, XTENSA_OPTION_DEPBITS)) {
+                if (!gen_window_check2(dc, RRR_S, RRR_T)) {
+                    break;
+                }
+                tcg_gen_deposit_i32(cpu_R[RRR_T], cpu_R[RRR_T], cpu_R[RRR_S],
+                                    OP2, RRR_R + 1);
+                break;
+            }
+
             HAS_OPTION(XTENSA_OPTION_FP_COPROCESSOR);
             switch (OP2) {
             case 0: /*ADD.Sf*/
@@ -2104,6 +2114,16 @@ static void disas_xtensa_insn(CPUXtensaState *env, 
DisasContext *dc)
             break;
 
         case 11: /*FP1*/
+            /*DEPBITS*/
+            if (option_enabled(dc, XTENSA_OPTION_DEPBITS)) {
+                if (!gen_window_check2(dc, RRR_S, RRR_T)) {
+                    break;
+                }
+                tcg_gen_deposit_i32(cpu_R[RRR_T], cpu_R[RRR_T], cpu_R[RRR_S],
+                                    OP2 + 16, RRR_R + 1);
+                break;
+            }
+
             HAS_OPTION(XTENSA_OPTION_FP_COPROCESSOR);
 
 #define gen_compare(rel, br, a, b) \
-- 
1.8.1.4