[Lldb-commits] [lldb] r183716 - <rdar://problem/12783351>

[Enrico Granata]

Author: enrico
Date: Mon Jun 10 19:18:18 2013
New Revision: 183716

URL: http://llvm.org/viewvc/llvm-project?rev=183716&view=rev
Log:
<rdar://problem/12783351>

Add support for half-floats, as specified by IEEE-754-2008
With this checkin, you can now say:
(lldb) x/7hf foo

to read 7 half-floats at address foo


Modified:
    lldb/trunk/include/lldb/lldb-enumerations.h
    lldb/trunk/source/Commands/CommandObjectMemory.cpp
    lldb/trunk/source/Core/DataExtractor.cpp
    lldb/trunk/source/DataFormatters/FormatManager.cpp

Modified: lldb/trunk/include/lldb/lldb-enumerations.h
URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/include/lldb/lldb-enumerations.h?rev=183716&r1=183715&r2=183716&view=diff
==============================================================================
--- lldb/trunk/include/lldb/lldb-enumerations.h (original)
+++ lldb/trunk/include/lldb/lldb-enumerations.h Mon Jun 10 19:18:18 2013
@@ -125,6 +125,7 @@ namespace lldb {
         eFormatAddressInfo,         // Describe what an address points to (func + offset with file/line, symbol + offset, data, etc)
         eFormatHexFloat,            // ISO C99 hex float string
         eFormatInstruction,         // Disassemble an opcode
+        eFormatHalfFloat,           // Half-floats (IEEE-754-2008 binary16 interchange format)
         eFormatVoid,                // Do not print this
         kNumFormats
     } Format;

Modified: lldb/trunk/source/Commands/CommandObjectMemory.cpp
URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/source/Commands/CommandObjectMemory.cpp?rev=183716&r1=183715&r2=183716&view=diff
==============================================================================
--- lldb/trunk/source/Commands/CommandObjectMemory.cpp (original)
+++ lldb/trunk/source/Commands/CommandObjectMemory.cpp Mon Jun 10 19:18:18 2013
@@ -180,12 +180,15 @@ public:
             case eFormatUnicode32:
             case eFormatUnsigned:
             case eFormatHexFloat:
+            case eFormatHalfFloat:
                 if (!byte_size_option_set)
                     byte_size_value = 4;
                 if (!num_per_line_option_set)
                     m_num_per_line = 1;
                 if (!count_option_set)
                     format_options.GetCountValue() = 8;
+                if (format_options.GetFormat() == eFormatFloat && byte_size_option_set && byte_size_value == 2)
+                    format_options.GetFormatValue().SetCurrentValue(eFormatHalfFloat);
                 break;
             
             case eFormatBytes:
@@ -1170,6 +1173,7 @@ protected:
             case eFormatComplexInteger:
             case eFormatAddressInfo:
             case eFormatHexFloat:
+            case eFormatHalfFloat:
             case eFormatInstruction:
             case eFormatVoid:
                 result.AppendError("unsupported format for writing memory");

Modified: lldb/trunk/source/Core/DataExtractor.cpp
URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/source/Core/DataExtractor.cpp?rev=183716&r1=183715&r2=183716&view=diff
==============================================================================
--- lldb/trunk/source/Core/DataExtractor.cpp (original)
+++ lldb/trunk/source/Core/DataExtractor.cpp Mon Jun 10 19:18:18 2013
@@ -1302,6 +1302,22 @@ DumpAPInt (Stream *s, const DataExtracto
     return offset;
 }
 
+static float half2float (uint16_t half)
+{
+    union{ float       f; uint32_t    u;}u;
+    int32_t v = (int16_t) half;
+    
+    if( 0 == (v & 0x7c00))
+    {
+        u.u = v & 0x80007FFFU;
+        return u.f * 0x1.0p125f;
+    }
+    
+    v <<= 13;
+    u.u = v | 0x70000000U;
+    return u.f * 0x1.0p-112f;
+}
+
 lldb::offset_t
 DataExtractor::Dump (Stream *s,
                      offset_t start_offset,
@@ -1712,6 +1728,24 @@ DataExtractor::Dump (Stream *s,
             }
             break;
 
+        case eFormatHalfFloat:
+            {
+                std::ostringstream ss;
+                if (item_byte_size == 2)
+                {
+                    uint16_t half = this->GetU16(&offset);
+                    float half_converted = half2float(half);
+                    ss << half_converted;
+                }
+                else
+                {
+                    s->Printf("error: unsupported byte size (%zu) for half-float format", item_byte_size);
+                    return offset;
+                }
+                ss.flush();
+                s->Printf("%s", ss.str().c_str());
+            }
+            break;
         case eFormatUnicode16:
             s->Printf("U+%4.4x", GetU16 (&offset));
             break;

Modified: lldb/trunk/source/DataFormatters/FormatManager.cpp
URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/source/DataFormatters/FormatManager.cpp?rev=183716&r1=183715&r2=183716&view=diff
==============================================================================
--- lldb/trunk/source/DataFormatters/FormatManager.cpp (original)
+++ lldb/trunk/source/DataFormatters/FormatManager.cpp Mon Jun 10 19:18:18 2013
@@ -72,6 +72,7 @@ g_format_infos[] =
     { eFormatCharArray      , 'a'   , "character array"     },
     { eFormatAddressInfo    , 'A'   , "address"             },
     { eFormatHexFloat       , '\0'  , "hex float"           },
+    { eFormatHalfFloat      , '\0'  , "half float"          },
     { eFormatInstruction    , 'i'   , "instruction"         },
     { eFormatVoid           , 'v'   , "void"                }
 };