5.35 · exercise

Bubble up the order

The starter reads a count and then that many values, in a tangle, into the word array tangle. Bubble sort them in place, smallest first; the print loop at the bottom will show whatever order the memory ends up in.

Bubble sort is two nested loops: the outer one counts passes, the inner one walks adjacent pairs, swapping any pair that is out of order. Both elements of a pair load with the scaled-index form, [base_r, j_r, sxtw 2], which adds the index times 4 (the size of a word) to the base address. A swap is storing them back in each other's slots. After each pass the largest remaining value has bubbled to the end, so the inner walk can shrink as the passes go by.

What is checked

  • the values, one per line, in ascending order
  • the program exits cleanly
  • the sort rearranges memory (str present, comparisons present)
  • the same holds for other arrays you do not see: one value, already sorted, reversed, and repeats

specification

stdin6 9 2 7 1 8 4
stdoutprints the right output
exitexits with the right code
sourceuses str
sourceuses cmp
hiddenright output and exit code on 4 more inputs you do not see

We run your program on the input above and on the hidden ones, and compare what it does. Nothing is matched against a stored solution.

loading editor...

regfile

N clearZ clearC clearV clear

x0–x30 are the integer registers.

X0arg00x0000000000000000
X1arg10x0000000000000000
X2arg20x0000000000000000
X3arg30x0000000000000000
X4arg40x0000000000000000
X5arg50x0000000000000000
X6arg60x0000000000000000
X7arg70x0000000000000000
X8ind0x0000000000000000
X90x0000000000000000
X100x0000000000000000
X110x0000000000000000
X120x0000000000000000
X130x0000000000000000
X140x0000000000000000
X150x0000000000000000
X16ip00x0000000000000000
X17ip10x0000000000000000
X18pr0x0000000000000000
X190x0000000000000000
X200x0000000000000000
X210x0000000000000000
X220x0000000000000000
X230x0000000000000000
X240x0000000000000000
X250x0000000000000000
X260x0000000000000000
X270x0000000000000000
X280x0000000000000000
X29fp0x0000000000000000
X30lr0x0000000000000000
SP0x0000000080000000
PC0x0000000000400000
console

Output prints here as your program runs.

Press step or run under the editor, or feed stdin from the box below.

not assembled

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