Print properly signed displacement in disassembler.

src/x64/disasm-x64.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 467 matching lines @@
         int scale, index, base;
         get_sib(sib, &scale, &index, &base);
         if (index == 4 && (base & 7) == 4 && scale == 0 /*times_1*/) {
           // index == rsp means no index. Only use sib byte with no index for
           // rsp and r12 base.
           AppendToBuffer("[%s]", NameOfCPURegister(base));
           return 2;
         } else if (base == 5) {
           // base == rbp means no base register (when mod == 0).
           int32_t disp = *reinterpret_cast<int32_t*>(modrmp + 2);
-          AppendToBuffer("[%s*%d+0x%x]",
+          AppendToBuffer("[%s*%d%s0x%x]",
                          NameOfCPURegister(index),
-                         1 << scale, disp);
+                         1 << scale,
+                         disp < 0 ? "-" : "+",
+                         disp < 0 ? -disp : disp);
           return 6;
         } else if (index != 4 && base != 5) {
           // [base+index*scale]
           AppendToBuffer("[%s+%s*%d]",
                          NameOfCPURegister(base),
                          NameOfCPURegister(index),
                          1 << scale);
           return 2;
         } else {
           UnimplementedInstruction();
           return 1;
         }
       } else {
         AppendToBuffer("[%s]", NameOfCPURegister(rm));
         return 1;
       }
       break;
     case 1:  // fall through
     case 2:
       if ((rm & 7) == 4) {
         byte sib = *(modrmp + 1);
         int scale, index, base;
         get_sib(sib, &scale, &index, &base);
         int disp = (mod == 2) ? *reinterpret_cast<int32_t*>(modrmp + 2)
-                              : *reinterpret_cast<char*>(modrmp + 2);
+                              : *reinterpret_cast<int8_t*>(modrmp + 2);
         if (index == 4 && (base & 7) == 4 && scale == 0 /*times_1*/) {
-          if (-disp > 0) {
-            AppendToBuffer("[%s-0x%x]", NameOfCPURegister(base), -disp);
-          } else {
-            AppendToBuffer("[%s+0x%x]", NameOfCPURegister(base), disp);
-          }
+          AppendToBuffer("[%s%s0x%x]",
+                         NameOfCPURegister(base),
+                         disp < 0 ? "-" : "+",
+                         disp < 0 ? -disp : disp);
         } else {
-          if (-disp > 0) {
-            AppendToBuffer("[%s+%s*%d-0x%x]",
-                           NameOfCPURegister(base),
-                           NameOfCPURegister(index),
-                           1 << scale,
-                           -disp);
-          } else {
-            AppendToBuffer("[%s+%s*%d+0x%x]",
-                           NameOfCPURegister(base),
-                           NameOfCPURegister(index),
-                           1 << scale,
-                           disp);
-          }
+          AppendToBuffer("[%s+%s*%d%s0x%x]",
+                         NameOfCPURegister(base),
+                         NameOfCPURegister(index),
+                         1 << scale,
+                         disp < 0 ? "-" : "+",
+                         disp < 0 ? -disp : disp);
         }
         return mod == 2 ? 6 : 3;
       } else {
         // No sib.
         int disp = (mod == 2) ? *reinterpret_cast<int32_t*>(modrmp + 1)
-                              : *reinterpret_cast<char*>(modrmp + 1);
-        if (-disp > 0) {
-        AppendToBuffer("[%s-0x%x]", NameOfCPURegister(rm), -disp);
-        } else {
-        AppendToBuffer("[%s+0x%x]", NameOfCPURegister(rm), disp);
-        }
+                              : *reinterpret_cast<int8_t*>(modrmp + 1);
+        AppendToBuffer("[%s%s0x%x]",
+                       NameOfCPURegister(rm),
+                       disp < 0 ? "-" : "+",
+                       disp < 0 ? -disp : disp);
         return (mod == 2) ? 5 : 2;
       }
       break;
     case 3:
       AppendToBuffer("%s", (this->*register_name)(rm));
       return 1;
     default:
       UnimplementedInstruction();
       return 1;
   }
@@ skipping 1371 matching lines @@
     for (int i = 6 - static_cast<int>(pc - prev_pc); i >= 0; i--) {
       fprintf(f, "  ");
     }
     fprintf(f, "  %s\n", buffer.start());
   }
 }
 
 }  // namespace disasm
 
 #endif  // V8_TARGET_ARCH_X64