Although it seems that nobody still uses it, the ENTER instruction is supported by all ia32 processors and valgrind chokes on it: vex x86->IR: unhandled instruction bytes: 0xC8 0x0 0x0 0x0 ==12372== valgrind: Unrecognised instruction at address 0x8049D37. The disassemble is: 8049d37: c8 00 00 00 enter $0x0,$0x0 The program runs perfectly without valgrind Below is a test program which triggers this error. Compile with: $ nasm -felf test.asm $ gcc -o test test.o $ valgrind ./test ---------- test.asm ----------- section .text global main main: enter 0, 0 leave ret ------------------------------- This is Debian bug http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=393235
Why should we add support for an instruction that nobody uses?