37 lines
1.3 KiB
Plaintext
37 lines
1.3 KiB
Plaintext
# Add the first 10 numbers, and return the result in the exit code.
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#
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# To run (from the subx directory):
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# $ subx translate examples/ex3.subx -o examples/ex3
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# $ subx run examples/ex3
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# Expected result:
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# $ echo $?
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# 55
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== code
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# instruction effective address register displacement immediate
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# . op subop mod rm32 base index scale r32
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# . 1-3 bytes 3 bits 2 bits 3 bits 3 bits 3 bits 2 bits 2 bits 0/1/2/4 bytes 0/1/2/4 bytes
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# result: EBX = 0
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bb/copy-to-EBX 0/imm32
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# counter: ECX = 1
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b9/copy-to-ECX 1/imm32
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$loop:
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# while (counter <= 10)
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81 7/subop/compare 3/mod/direct 1/rm32/ECX . . . . . 0xa/imm32 # compare ECX
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7f/jump-if-greater $exit/disp8
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# result += counter
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01/add 3/mod/direct 3/rm32/EBX . . . 1/r32/ECX . . # add ECX to EBX
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# ++counter
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41/inc-ECX
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# loop
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eb/jump $loop/disp8
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$exit:
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# syscall(exit, EBX)
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b8/copy-to-EAX 1/imm32/exit
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cd/syscall 0x80/imm8
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# . . vim:nowrap:textwidth=0
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