From 6e1eeeebfb453fa7c871869c19375ce60fbd7413 Mon Sep 17 00:00:00 2001 From: Kartik Agaram Date: Sat, 27 Jul 2019 16:01:55 -0700 Subject: 5485 - promote SubX to top-level --- examples/ex6.subx | 37 +++++++++++++++++++++++++++++++++++++ 1 file changed, 37 insertions(+) create mode 100644 examples/ex6.subx (limited to 'examples/ex6.subx') diff --git a/examples/ex6.subx b/examples/ex6.subx new file mode 100644 index 00000000..a90f11df --- /dev/null +++ b/examples/ex6.subx @@ -0,0 +1,37 @@ +# Print out a (global variable) string to stdout. +# +# To run (from the subx directory): +# $ ./subx translate examples/ex6.subx -o examples/ex6 +# $ ./subx run examples/ex6 +# Hello, world! + +== code 0x09000000 +# instruction effective address register displacement immediate +# . op subop mod rm32 base index scale r32 +# . 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 + +Entry: + # syscall(write, stdout, X, Size) + # . fd = 1 (stdout) + bb/copy-to-EBX 1/imm32 + # . initialize X (location to write result to) + b9/copy-to-ECX X/imm32 + # . initialize Size + 8b/copy 0/mod/indirect 5/rm32/.disp32 . . 2/r32/EDX Size/disp32 . # copy *Size to EDX + # . syscall + b8/copy-to-EAX 4/imm32/write + cd/syscall 0x80/imm8 + + # syscall(exit, EBX) + b8/copy-to-EAX 1/imm32/exit + cd/syscall 0x80/imm8 + +== data 0x0a000000 + +Size: # size of string + 0x0e/imm32 # 14 +X: # string to print + 48 65 6c 6c 6f 2c 20 77 6f 72 6c 64 21 0a 00 +# H e l l o , ␣ w o r l d ! newline null + +# . . vim:nowrap:textwidth=0 -- cgit 1.4.1-2-gfad0