diff options
Diffstat (limited to 'linux/ex6.subx')
| -rw-r--r-- | linux/ex6.subx | 35 |
1 files changed, 35 insertions, 0 deletions
diff --git a/linux/ex6.subx b/linux/ex6.subx new file mode 100644 index 00000000..585362f1 --- /dev/null +++ b/linux/ex6.subx @@ -0,0 +1,35 @@ +# Print out a (global variable) string to stdout. +# +# To run: +# $ ./bootstrap translate init.linux apps/ex6.subx -o apps/ex6 +# $ ./bootstrap run apps/ex6 +# Hello, world! + +== code + +# . 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: + # 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 + e8/call syscall_write/disp32 + + # exit(ebx) + e8/call syscall_exit/disp32 + +== data + +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 |