While compiling a FreeBSD kernel I encountered the following error message from GNU assembler
\n[shell]
\nError: suffix or operands invalid for ‘mov’
\n[\/shell]<\/p>\n
I was not sure whether the error is because of my changes are not. But still I have to debug the problem and solve it, so I decided to find what is wrong with the mov <\/em>instruction. But since gcc created a temporary file and invoked as to assemble it, I couldn\u2019t find the temp file anymore.<\/p>\n Googled and find the following gcc options to find what gcc does.<\/p>\n gcc \u2013v<\/strong> is verbose mode, which prints all the action\/scripts gcc is doing. With gcc \u2013v \u2013save-temps, I got the temporary assembler file used by assembler. Since reading machine generated assembly file is difficult, I tried to find the C source code corresponding to the error. From nearest .file assembler directive<\/a> I found the C file name and from the .loc directive I found the line number. And the following was the inline assembly in the C file.
\ngcc -###<\/strong> similar to \u2013v but wont execute any commands.
\ngcc \u2013save-temps<\/strong> saves all the temporary files generated by the gcc. Useful if you want to see the assembly output passed to gnu assembler.
\ngcc \u2013E<\/strong> Just preprocess the c file.
\ngcc \u2013S<\/strong> generate assembly file.<\/p>\n
\n[c]__asm __volatile(“movl <\/b>%%ss,%0″ : “=rm” (sel));[\/c]<\/p>\n