[Lldb-commits] [lldb] r125508 - /lldb/trunk/source/Plugins/Process/Utility/ARMUtils.h

[Johnny Chen]

Author: johnny
Date: Mon Feb 14 13:08:41 2011
New Revision: 125508

URL: http://llvm.org/viewvc/llvm-project?rev=125508&view=rev
Log:
Enhanced the existing ARMExpandImm() and ThumbExpandImm() functions which expand
an imm12 into imm32 for ARM or Thumb so that they now handle carry_in/carry_out.
Funnel ARMExpandImm()/ThumbExpandImm() to the enhanced ARMExpandImm_C()/ThumbExpandImm_C()
functions.

Modified:
    lldb/trunk/source/Plugins/Process/Utility/ARMUtils.h

Modified: lldb/trunk/source/Plugins/Process/Utility/ARMUtils.h
URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/source/Plugins/Process/Utility/ARMUtils.h?rev=125508&r1=125507&r2=125508&view=diff
==============================================================================
--- lldb/trunk/source/Plugins/Process/Utility/ARMUtils.h (original)
+++ lldb/trunk/source/Plugins/Process/Utility/ARMUtils.h Mon Feb 14 13:08:41 2011
@@ -32,47 +32,78 @@
     return (val >> m) | (val << (N - m));
 }
 
-static inline uint32_t ARMExpandImm(uint32_t val)
+// (imm32, carry_out) = ARMExpandImm_C(imm12, carry_in)
+static inline uint32_t ARMExpandImm_C(uint32_t val, uint32_t carry_in, uint32_t &carry_out)
 {
+    uint32_t imm32;                      // the expanded result
     uint32_t imm = bits(val, 7, 0);      // immediate value
-    uint32_t rot = 2 * bits(val, 11, 8); // rotate amount
-    return (imm >> rot) | (imm << (32 - rot));
+    uint32_t amt = 2 * bits(val, 11, 8); // rotate amount
+    if (amt == 0)
+    {
+        imm32 = imm;
+        carry_out = carry_in;
+    }
+    else
+    {
+        imm32 = ror(imm, 32, amt);
+        carry_out = Bit32(imm32, 31);
+    }
+    return imm32;
 }
 
-static inline uint32_t ThumbExpandImm(uint32_t val)
+static inline uint32_t ARMExpandImm(uint32_t val)
 {
-  uint32_t imm32 = 0;
-  const uint32_t i = bit(val, 26);
-  const uint32_t imm3 = bits(val, 14, 12);
-  const uint32_t abcdefgh = bits(val, 7, 0);
-  const uint32_t imm12 = i << 11 | imm3 << 8 | abcdefgh;
+    // 'carry_in' argument to following function call does not affect the imm32 result.
+    uint32_t carry_in = 0;
+    uint32_t carry_out;
+    return ARMExpandImm_C(val, carry_in, carry_out);
+}
 
-  if (bits(imm12, 10, 11) == 0)
-  {
-      switch (bits(imm12, 8, 9)) {
-      case 0:
-          imm32 = abcdefgh;
-          break;
-
-      case 1:
-          imm32 = abcdefgh << 16 | abcdefgh;
-          break;
-
-      case 2:
-          imm32 = abcdefgh << 24 | abcdefgh << 8;
-          break;
-
-      case 3:
-          imm32 = abcdefgh  << 24 | abcdefgh << 16 | abcdefgh << 8 | abcdefgh; 
-          break;
-      }
-  }
-  else
-  {
-      const uint32_t unrotated_value = 0x80 | bits(imm12, 0, 6);
-      imm32 = ror(unrotated_value, 32, bits(imm12, 7, 11));
-  }
-  return imm32;
+// (imm32, carry_out) = ThumbExpandImm_C(imm12, carry_in)
+static inline uint32_t ThumbExpandImm_C(uint32_t val, uint32_t carry_in, uint32_t &carry_out)
+{
+    uint32_t imm32;
+    const uint32_t i = bit(val, 26);
+    const uint32_t imm3 = bits(val, 14, 12);
+    const uint32_t abcdefgh = bits(val, 7, 0);
+    const uint32_t imm12 = i << 11 | imm3 << 8 | abcdefgh;
+
+    if (bits(imm12, 11, 10) == 0)
+    {
+        switch (bits(imm12, 8, 9)) {
+        case 0:
+            imm32 = abcdefgh;
+            break;
+
+        case 1:
+            imm32 = abcdefgh << 16 | abcdefgh;
+            break;
+
+        case 2:
+            imm32 = abcdefgh << 24 | abcdefgh << 8;
+            break;
+
+        case 3:
+            imm32 = abcdefgh  << 24 | abcdefgh << 16 | abcdefgh << 8 | abcdefgh; 
+            break;
+        }
+        carry_out = carry_in;
+    }
+    else
+    {
+        const uint32_t unrotated_value = 0x80 | bits(imm12, 6, 0);
+        imm32 = ror(unrotated_value, 32, bits(imm12, 11, 7));
+        carry_out = Bit32(imm32, 31);
+    }
+    return imm32;
+}
+
+static inline uint32_t ThumbExpandImm(uint32_t val)
+{
+    // 'carry_in' argument to following function call does not affect the imm32 result.
+    uint32_t carry_in = 0;
+    uint32_t carry_out;
+    return ThumbExpandImm_C(val, carry_in, carry_out);
 }
 
 // imm32 = ZeroExtend(i:imm3:imm8, 32)