Firstly, you might want to check this quick MIPS reference. It really helped me. Secondly, to explain jal, jr and $ra. What jal <label> does is jump to the label label and store the program counter (think of it as the address of the current instruction) in the $ra register. Now, when you want to … Read more
Shifting a number n bits left multiples the number by 2n. For example n << 3 = n*2³ = n*8. The corresponding instruction is To multiply any number you can split the number into sums of power of 2s. For example: n*10 = n*8 + n*2 = (n << 3) + (n << 1) SLL … Read more
This link explains how to print to the screen in a MIPS simulator like QTSPIM or MARS. As for the code, there were a few bugs. The line li $a0, 0 is overwriting the work done by the initial la $a0, Array instruction because the li is setting the base address of your array to 0. Instead, you should move the la instruction into the loop so … Read more
If you’re just trying to print a newline, it’s simpler (and slightly more memory efficient) to do it using syscall 11 to print a single character.
The addi instruction requires an immediate operand rather than a register, so the $0 would actually be 0: Both will work and have all the needed information encoded into the instruction itself): However, it would be more usual to just use the zero-locked $0 register in this particular case since that is, after all, its purpose. I would also tend to use the unsigned variant however, since I … Read more
2 I’m trying to write a simple code which save string and integer input into an array and then prints them (i will also later add another part which sorts them,but i have to get this to work first). With MARS i get this: line 75: Runtime exception at 0x004000e4: address out of range 0x00000008. … Read more
add adds the value in two registers addi adds an immediate value (constant) to the register This gives you some example.
You didn’t store the numbers entered in the variables. Also, the print_int syscall expects number in $a0 so when you try to print the second number from $a1 it won’t work.
According to the MIPS instruction reference, the only addition operations which can produce overflow exceptions are the signed addition instructions: MIPS integers are 32-bit, and since you’ll be using signed integers, the maximum value is 231-1 (aka 2147483647 or hex 7FFFFFFF). Thus any addition which results in a number larger than this should throw an exception, … Read more
MIPS instruction set doesn’t provide a mult instruction with immediate value. Hence you would have to store the value into a temporary register and then use mult instructions. The result of the mult instruction would be stored in lo and hi registers giving the lower 32-bit of the result and upper 32-bit of the result … Read more