comparison failure

[lonelyjohner]

the add16 run and failed. At the bottom program indicated that the comparison failure.
I wondered What could be the potential trigger of it? Thx.

[cadet1620]

lonelyjohner wrote

the add16 run and failed. At the bottom program indicated that the comparison failure.
I wondered What could be the potential trigger of it? Thx.

Select View: Output and see what your Add16 is outputting. Select View: Compare to see what it should be outputting.
Sometimes it is easier to open Add16.cmp and Add16.out simultaneously in a text editor to compare them.

Also be aware that hardware bits are numbered from least to most signigicant. a[0] is the 2^0 bit and a[15] is the 2^15 bit.

--Mark

[lonelyjohner]

I see. I mistakenly type the 14th-way of input b to its 15th position. But it does not make any grammar mistake.I thought it should run to the end and just show different results. Does this mean even if there is little difference between comparison and output the program will treat it pretty "seriously" like some kind of grammar error?

At 2013-12-30 22:06:06,"cadet1620 [via Nand2Tetris Questions and Answers Forum]" <[hidden email]> wrote:

lonelyjohner wrote

the add16 run and failed. At the bottom program indicated that the comparison failure.
I wondered What could be the potential trigger of it? Thx.

Select View: Output and see what your Add16 is outputting. Select View: Compare to see what it should be outputting.
Sometimes it is easier to open Add16.cmp and Add16.out simultaneously in a text editor to compare them.

Also be aware that hardware bits are numbered from least to most signigicant. a[0] is the 2^0 bit and a[15] is the 2^15 bit.

--Mark

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[cadet1620]

lonelyjohner wrote

I see. I mistakenly type the 14th-way of input b to its 15th position. But it does not make any grammar mistake.I thought it should run to the end and just show different results. Does this mean even if there is little difference between comparison and output the program will treat it pretty "seriously" like some kind of grammar error?

The test will pause whenever there is a miscompare. You can use the step or run command to continue the test. It will stop again on the next miscompare.

This is more or less like a program that compiles correctly but fails during runtime, say with a divide-by-zero error.

--Mark

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