Hello colleagues, I have an application that performs like objdump. I mean: it takes the 32bits of each ppc instruction and then generates the string of assembled instruction.
On branch-conditional (bc) instructions the generated objdump string shows diferent branch hint for the same opcode. Example: objdump output: ... 10000480: 40 9e 00 5c bne- cr7,0x100004dc ... 100004b4: 40 9e ff e4 bne+ cr7,0x10000498 ... However, I hace compiled the following assembly code to check the error: bne- cr7,. bne+ cr7,. and the objdump output is: 0: 40 9e 00 00 bne- cr7,0x0 4: 40 be 00 00 bne+ cr7,0x4 Now its, at least, the opcode it's different. If we analyse the BO field (following the PowerPC 2.01 architecture description) of the instruction, it does not correspond to the documentation. opcode: 40 9e 00 5c --> BO: 4 documentation: no hint Objdump hint: no taken 40 9e ff e4 --> BO: 4 documentation: no hint Objdump hint: taken 40 9e 00 00 --> BO: 4 documentation: no hint Objdump hint: no taken 40 be 00 00 --> BO: 5 documentation: reserved Objdump hint: taken In addition, I tried to compile with gcc4.0.2 the following assembly: bc 4,2,. bc 6,2,. bc 7,2,. Following the documentation, the instructions shoud be: bne $address bne- $address bne+ $address However it does not compile. The second and third instruction are not recognized. In conclusion, I guess I'm missing something. Do gcc and objdump follow the architecture documentation? (which version?) If they really have to follow the documentation, there is a bug on binutils (objdump and as). Well, sorry for the large explanation and thanks in advance. Salut! Ramon. _______________________________________________ bug-binutils mailing list bug-binutils@gnu.org http://lists.gnu.org/mailman/listinfo/bug-binutils
