diff options
Diffstat (limited to 'linux/apps/ex3.subx')
| -rw-r--r-- | linux/apps/ex3.subx | 36 |
1 files changed, 36 insertions, 0 deletions
diff --git a/linux/apps/ex3.subx b/linux/apps/ex3.subx new file mode 100644 index 00000000..f4b5fed7 --- /dev/null +++ b/linux/apps/ex3.subx @@ -0,0 +1,36 @@ +# Add the first 10 numbers, and return the result in the exit code. +# +# To run: +# $ bootstrap/bootstrap translate apps/ex3.subx -o ex3 +# $ bootstrap/bootstrap run ex3 +# Expected result: +# $ echo $? +# 55 + +== code +# instruction effective address register displacement immediate +# . op subop mod rm32 base index scale r32 +# . 1-3 bytes 3 bits 2 bits 3 bits 3 bits 3 bits 2 bits 2 bits 0/1/2/4 bytes 0/1/2/4 bytes + +Entry: + # result: ebx = 0 + bb/copy-to-ebx 0/imm32 + # counter: ecx = 1 + b9/copy-to-ecx 1/imm32 + +$loop: + # if (counter > 10) break + 81 7/subop/compare 3/mod/direct 1/rm32/ecx . . . . . 0xa/imm32 # compare ecx + 7f/jump-if-> $exit/disp8 + # result += counter + 01/add 3/mod/direct 3/rm32/ebx . . . 1/r32/ecx . . # add ecx to ebx + # ++counter + 41/increment-ecx + # loop + eb/jump $loop/disp8 + +$exit: + # exit(ebx) + e8/call syscall_exit/disp32 + +# . . vim:nowrap:textwidth=0 |