#include "dump.h" int main ( int argc, char* argv[] ) { __asm { mov eax, 1// init eax to 1 mov ebx, esp; keep a copy of esp mov ecx, 3/* init ecx to 3 */ mov edx, 4; init edx to 4 } dump(); //show reg contents return 0; } provided by me, your kind professor

The VC++ inline Assembler is only a small subset of MASM. What's allowed: 1. line labels must always end with : 2. instruction opcodes and operands 3. comments (both ; and C-style) 4. align and even simply inserts NOPs, if necessary 5. length, size, and type 6. references to C variables & functions

The VC++ inline Assembler is only a small subset of MASM. What's not allowed: 1. data definitions(use C++ instead) 2. macros(use C++ instead) 3. conditional assembly(use C++ instead) 4. local line labels 5. and much, much more

While debugging...  We can view our inline Assembler!  We can also see the Assembler code generated by the compiler corresponding to our C code!

 Assembler generated from the same C/C++ source code is different for Debug and Release versions!  Release version is optimized but doesn’t contain any debugging information.  Check size of debug and release.exe’s. (They are different!)  Turn on generation of Assembler listing (.cod) files and take a look.

 This is very instructive: 1. for learning Assembler 2. as a starting point for improvement (optimization)

 In Microsoft Visual C Express, 1. Turn on expert mode. Tools  Settings  Expert settings 2. Set a breakpoint in your program. 3. Start debugging your program. 4. View disassembly and registers. Debug  Windows  Disassembly Debug  Windows  Registers To display f.p. or XMM registers, right-click in Registers window.

#include clock_t start = clock(); for (int i=0; i<N; i++) { __asm { ; do something useful } clock_t delta = clock() - start; double elapsed = ((double)delta) / CLOCKS_PER_SEC; printf( "elapsed = %f sec (%d ticks) \n", elapsed, delta ); printf( " " ); getchar();

 AMD CodeAnalyst ( /Pages/default.aspx)  ats-the-best-free-c-profiler-for-windows-if- there-are

 javap (javap.exe)  JDK program used to disassemble.class files.  Steps: 1. Compile first (using javac) to produce.class file(s). 2. Then javap –verbose Test (to disassemble Test.class).

 javap example class Test { public static void main ( String[] args ) { for (int i=0; i<10; i++) { System.out.printf( "i = %d \n", i ); } … public static void main(java.lang.String[]); Code: Stack=6, Locals=2, Args_size=1 0:iconst_0 1:istore_1 2:iload_1 3:bipush10 5:if_icmpge34 8:getstatic#2; //Field java/lang/System.out:Ljava/io/PrintStream; 11:ldc#3; //String i = %d \n 13:iconst_1 14:anewarray#4; //class java/lang/Object 17:dup 18:iconst_0 19:iload_1 20:invokestatic#5; //Method java/lang/Integer.valueOf:(I)Ljava/lang/Integer; 23:aastore 24:invokevirtual#6; //Method java/io/PrintStream.printf:(Ljava/lang/String;[Ljava/lang/Object;)Ljava/io/PrintStream; 27:pop 28:iinc1, 1 31:goto2 34:return …

 use System class for timing:  System.currentTimeMillis() returns (a long) the current time in milliseconds  System.nanoTime() returns (a long) the current value of the most precise available system timer, in nanoseconds but may be wrong for timing longer algorithms (Why?)

 utilties.asm contains:  call dump shows the contents of registers  call rand8 returns a random number in eax in the range [0..255]  call resetTime sets elapsed time timer back to zero  call reportTime reports elapsed time in milliseconds