1 # Add the first 10 numbers, and return the result in the exit code. 2 # 3 # To run (from the subx directory): 4 # $ ./subx translate examples/ex3.subx -o examples/ex3 5 # $ ./subx run examples/ex3 6 # Expected result: 7 # $ echo $? 8 # 55 9 10 == code 11 # instruction effective address register displacement immediate 12 # . op subop mod rm32 base index scale r32 13 # . 1-3 bytes 3 bits 2 bits 3 bits 3 bits 3 bits 2 bits 2 bits 0/1/2/4 bytes 0/1/2/4 bytes 14 15 # result: EBX = 0 16 bb/copy-to-EBX 0/imm32 17 # counter: ECX = 1 18 b9/copy-to-ECX 1/imm32 19 20 $loop: 21 # if (counter > 10) break 22 81 7/subop/compare 3/mod/direct 1/rm32/ECX . . . . . 0xa/imm32 # compare ECX 23 7f/jump-if-greater $exit/disp8 24 # result += counter 25 01/add 3/mod/direct 3/rm32/EBX . . . 1/r32/ECX . . # add ECX to EBX 26 # ++counter 27 41/inc-ECX 28 # loop 29 eb/jump $loop/disp8 30 31 $exit: 32 # syscall(exit, EBX) 33 b8/copy-to-EAX 1/imm32/exit 34 cd/syscall 0x80/imm8 35 36 # . . vim:nowrap:textwidth=0