From: Julian Seward <jseward@acm.org>
Date: Mon, 17 Aug 2015 13:55:41 +0000 (+0000)
Subject: Implement YIELD (encodings T1 and A1).  Fixes #348377.
X-Git-Tag: svn/VALGRIND_3_11_0^2~14
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=2d33c6dd48b8160d367743906b181ced87cfcc8b;p=thirdparty%2Fvalgrind.git

Implement YIELD (encodings T1 and A1).  Fixes #348377.


git-svn-id: svn://svn.valgrind.org/vex/trunk@3177
---

diff --git a/VEX/priv/guest_arm_toIR.c b/VEX/priv/guest_arm_toIR.c
index 94f8de071d..d05276408f 100644
--- a/VEX/priv/guest_arm_toIR.c
+++ b/VEX/priv/guest_arm_toIR.c
@@ -16782,12 +16782,6 @@ DisResult disInstr_ARM_WRK (
       }
    }
 
-   /* ------------------- NOP ------------------ */
-   if (0x0320F000 == (insn & 0x0FFFFFFF)) {
-      DIP("nop%s\n", nCC(INSN_COND));
-      goto decode_success;
-   }
-
    /* -------------- (A1) LDRT reg+/-#imm12 -------------- */
    /* Load Register Unprivileged:
       ldrt<c> Rt, [Rn] {, #+/-imm12}
@@ -17280,6 +17274,30 @@ DisResult disInstr_ARM_WRK (
          break;
    }
 
+   /* ----------------------------------------------------------- */
+   /* -- Hints                                                 -- */
+   /* ----------------------------------------------------------- */
+
+   switch (insn & 0x0FFFFFFF) {
+      /* ------------------- NOP ------------------ */
+      case 0x0320F000:
+         DIP("nop%s\n", nCC(INSN_COND));
+         goto decode_success;
+      /* ------------------- YIELD ------------------ */
+      case 0x0320F001:
+         /* Continue after conditionally yielding. */
+         DIP("yield%s\n", nCC(INSN_COND));
+         stmt( IRStmt_Exit( unop(Iop_32to1, 
+                                 condT == IRTemp_INVALID 
+                                    ? mkU32(1) : mkexpr(condT)),
+                            Ijk_Yield,
+                            IRConst_U32(guest_R15_curr_instr_notENC + 4),
+                            OFFB_R15T ));
+         goto decode_success;
+      default:
+         break;
+   }
+
    /* ----------------------------------------------------------- */
    /* -- VFP (CP 10, CP 11) instructions (in ARM mode)         -- */
    /* ----------------------------------------------------------- */
@@ -19170,16 +19188,18 @@ DisResult disInstr_THUMB_WRK (
          /* ------ NOP ------ */
          DIP("nop\n");
          goto decode_success;
-      case 0xBF20:
-         /* ------ WFE ------ */
-         /* WFE gets used as a spin-loop hint.  Do the usual thing,
+      case 0xBF10: // YIELD
+      case 0xBF20: // WFE
+         /* ------ WFE, YIELD ------ */
+         /* Both appear to get used as a spin-loop hints.  Do the usual thing,
             which is to continue after yielding. */
          stmt( IRStmt_Exit( unop(Iop_32to1, mkexpr(condT)),
                             Ijk_Yield,
                             IRConst_U32((guest_R15_curr_instr_notENC + 2) 
                                         | 1 /*CPSR.T*/),
                             OFFB_R15T ));
-         DIP("wfe\n");
+         Bool isWFE = INSN0(15,0) == 0xBF20;
+         DIP(isWFE ? "wfe\n" : "yield\n");
          goto decode_success;
       case 0xBF40:
          /* ------ SEV ------ */