From 72523cbefe1abdb2876f328fdcb8be7f77dcf458 Mon Sep 17 00:00:00 2001
From: Julian Seward <jseward@acm.org>
Date: Sun, 5 Mar 2006 19:20:08 +0000
Subject: [PATCH] merge r1579 (Implement mtocrf/mfocrf.)

git-svn-id: svn://svn.valgrind.org/vex/branches/VEX_3_1_BRANCH@1580
---
 VEX/priv/guest-ppc32/toIR.c | 47 ++++++++++++++++++++++++++++---------
 1 file changed, 36 insertions(+), 11 deletions(-)

diff --git a/VEX/priv/guest-ppc32/toIR.c b/VEX/priv/guest-ppc32/toIR.c
index a251cf37e4..bfa0b4f777 100644
--- a/VEX/priv/guest-ppc32/toIR.c
+++ b/VEX/priv/guest-ppc32/toIR.c
@@ -3760,14 +3760,23 @@ static Bool dis_proc_ctl ( UInt theInstr )
       break;
    }
       
-   case 0x013: // mfcr (Move from Condition Register, PPC32 p467)
-      if (b11to20 != 0) {
-         vex_printf("dis_proc_ctl(PPC32)(mfcr,b11to20)\n");
-         return False;
+   case 0x013:
+      // b11to20==0:      mfcr (Move from Cond Register, PPC32 p467)
+      // b20==1 & b11==0: mfocrf (Move from One CR Field)
+      // However it seems that the 'mfcr' behaviour is an acceptable
+      // implementation of mfocr (from the 2.02 arch spec)
+      if (b11to20 == 0) {
+         DIP("mfcr r%u\n", rD_addr);
+         putIReg( rD_addr, getSPR( PPC32_SPR_CR ) );
+         break;
       }
-      DIP("mfcr r%d\n", rD_addr);
-      putIReg( rD_addr, getSPR( PPC32_SPR_CR ) );
-      break;
+      if (b20 == 1 && b11 == 0) {
+         DIP("mfocrf r%u,%u\n", rD_addr, CRM);
+         putIReg( rD_addr, getSPR( PPC32_SPR_CR ) );
+         break;
+      }
+      /* not decodable */
+      return False;
       
    /* XFX-Form */
    case 0x153: // mfspr (Move from Special-Purpose Register, PPC32 p470)
@@ -3838,14 +3847,27 @@ static Bool dis_proc_ctl ( UInt theInstr )
       break;
    }
 
-   case 0x090: { // mtcrf (Move to Condition Register Fields, PPC32 p477)
+   case 0x090: {
+      // b20==0: mtcrf (Move to Cond Register Fields, PPC32 p477)
+      // b20==1: mtocrf (Move to One Cond Reg Field)
       Int   cr;
       UChar shft;
-      if (b11 != 0 || b20 != 0) {
-         vex_printf("dis_proc_ctl(PPC32)(mtcrf,b11|b20)\n");
+      if (b11 != 0)
          return False;
+      if (b20 == 1) {
+         /* ppc64 v2.02 spec says mtocrf gives undefined outcome if >
+            1 field is written.  It seems more robust to decline to
+            decode the insn if so. */
+         switch (CRM) {
+            case 0x01: case 0x02: case 0x04: case 0x08:
+            case 0x10: case 0x20: case 0x40: case 0x80:
+               break;
+            default:
+               return False;
+         }
       }
-      DIP("mtcrf 0x%x,r%d\n", CRM, rS_addr);
+      DIP("%s 0x%x,r%u\n", b20==1 ? "mtocrf" : "mtcrf",
+                           CRM, rS_addr);
       /* Write to each field specified by CRM */
       for (cr = 0; cr < 8; cr++) {
          if ((CRM & (1 << (7-cr))) == 0)
@@ -3857,6 +3879,9 @@ static Bool dis_proc_ctl ( UInt theInstr )
       break;
    }
 
+
+
+
    case 0x1D3: // mtspr (Move to Special-Purpose Register, PPC32 p483)
       
       switch (SPR) {  // Choose a register...
-- 
2.47.2