ANDI | test web content for accessibility and 508 compliance | Accessibility Testing library

There are two coding errors:
Fix them this way

1. This was a bad nor expression

   regC = ~(regA | regB) ;

2. Was missing begin/end pairs

Like this

You've got this instruction andi $t0, $v0, 1 in your loop. But $v0 never changes within the loop, so you're always getting the same value. And regardless of whether that values was 0 or 1, it's going to be 0 after the srl on the following line.

The whole bit-counting loop could be replaced by something like this:

As Michael commented, integers in registers are already in binary. A register is a group of 32 bits.

Crucially, operations on registers like andi $t1, $v0, 1 and srl $v0, $v0, 1 work in binary. i.e. the resulting 0 or 1 from and is the value mod 2, and right-shift by 1 place divides by 2.

This is a consequence of MIPS being a binary computer, like every over real-world ISA you might learn assembly for. Higher-level languages including C, Java, and Python that have & and >> operations also always guarantee that they work in binary. (On a non-binary computer, e.g. ternary, implementing those semantics for x & y would involve converting to an array of base-2 digits and doing the logic manually, then converting back.)

If you want to work with other number bases, like base 10, you'd need to do actual division (MIPS divu) or remainder to remove or isolate the lowest base-10 digit. Or if the base is a power of 2, like base 16, then shift by 4 bits, or AND with 0x0f (take the low 4 bits, i.e. 0b1111).

Input / output in other bases involves converting (binary) integers from / to strings of ASCII digits representing digits in another base. The MARS/SPIM read_int call (syscall with $v0 = 5) does that for you, like C library functions scanf or printf. To do it manually, you do stuff like total = total * 10 + digit, where digit is something like ascii_char - '0'. Or for output, repeated division / modulo by 10 to get the base-10 digits, starting with the lowest.

There are some MIPS Q&As about manually converting to/from strings, but not many because most students using MIPS are using MARS or SPIM with their toy system calls that do things normally done by a C library, or by hand. But IIRC there are some if you search.

ASCII decimal or hex strings are a serialization format for numbers, not how they exist inside computers (except as strings, not integers).

Looping over the bits one at a time, extracting and adding the low bit, is a simple but often inefficient way to count the number of set bits. Still, simple is good for a first attempt; the choice of andi and srl as examples earlier is a hint.

Some faster bithacks are shown on How to count the number of set bits in a 32-bit integer? although for MIPS that means generating lots of separate 32-bit constants which cost 2 instructions each. You could do two SWAR widening steps and then loop over groups of 4-bit sums, as a middle ground.

Count bits 1 on an integer as fast as GCC __builtin__popcount(int) shows a way where you count iterations of n &= n-1 to clear the lowest set bit, which is faster if there are only a few bits set, even if they're not near the bottom of the register.

The MIPS processor cannot do that operation in one instruction.  The andi instruction is an I-Type instruction, which holds a 16-bit immediate — further the andi instruction zero extends the 16-bit immediate to 32-bit, so it cannot hold a negative number (ori & xori also zero extend, whereas addi and all the others sign extend the immediate).

Whenever we cannot do something in one instruction, use a sequence of instructions.  In this case, load the immediate into a register, then use the and R-Type instruction.

FYI, the MARS simulator's assembler will take the andi $t1, $t0, 0xfffffff0, though it treats that as a pseudo instruction and will expand that one line of assembly into a 3-instruction machine code sequence that loads the constant into a register (using two instructions: one more than needed to do the job), then uses that and.

Apparently, Spim doesn't offer that particular pseudo instruction.

By default, an ontology is saved in the same place it was loaded from - in this case it was loaded from a remote IRI, and there's currently no support for saving an ontology directly to a remote URL.

You can work around this by specifying a target for your saveOntology() call, e.g.,

Using dplyr for the pipe and mutate, we can gsub everything after /.

The problem is that you are using unbounded parameters. For example, if you allow L to be negative, you can fit a monotonically decreasing dataset with your function.

If I add simple non-negativity bounds to your fit, I get:

If I understand you correctly, you can use a nested dictionary comprehension:

I am not 100% sure I understand your question. But, you can enter an array formula once and it will automatically fill in formulas below. So change this: