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| author | Kartik Agaram <vc@akkartik.com> | 2018-07-07 14:31:56 -0700 |
|---|---|---|
| committer | Kartik Agaram <vc@akkartik.com> | 2018-07-07 14:31:56 -0700 |
| commit | 97a9bd1756d5ea934372847bb9f1dfa8a4ad256d (patch) | |
| tree | 359caa004ebc46ce1bfe9d6e1c6054e395567604 /subx/ex3.subx | |
| parent | bc394aaf39da72d980933a720b6deb8876036c07 (diff) | |
| download | mu-97a9bd1756d5ea934372847bb9f1dfa8a4ad256d.tar.gz | |
4324 - new example: add first ten numbers
Result has to be small enough to fit in AL so exit() can return it.
Diffstat (limited to 'subx/ex3.subx')
| -rw-r--r-- | subx/ex3.subx | 23 |
1 files changed, 23 insertions, 0 deletions
diff --git a/subx/ex3.subx b/subx/ex3.subx new file mode 100644 index 00000000..df793f5d --- /dev/null +++ b/subx/ex3.subx @@ -0,0 +1,23 @@ +## add the first 10 numbers + +# opcode ModR/M SIB displacement immediate +# instruction mod, reg, Reg/Mem bits scale, index, base +# 1-3 bytes 0/1 byte 0/1 byte 0/1/2/4 bytes 0/1/2/4 bytes + # result: EBX +# 0: e_entry = 0x08048054 + bb 0/imm32 # copy 0 to EBX + # counter: ECX + b9 1/imm32 # copy 1 to ECX + +# 10: loop: 0x0804805e + 81 f9 10/imm32 # compare ECX, 10/imm + 7f 0a # jump-if-greater exit (+10) + 01 cb # add ECX to EBX + 81 c1 1/imm32 # add 1 to ECX + eb ee # jump loop (-18; -00010010; 11101110) + +# 28: exit: 0x08048070 + b8 1/imm32 # copy 1 to EAX + cd 128/imm8 # int 80h + +# vim:ft=subx:nowrap |