MIPS convert float into an integer

Question

I've tried looking at it a couple different ways, one of them was using binary to shift left/right but I just wasn't able to find a combination to make it work for anything besides a few selected numbers each time. So how do you convert a float into an integer?

.data
five: .float 10.0

.text

main:
    la  $a1 five 
    l.s $f12 ($a1) 
    #conversion here

    li $v0 2# print float, which will print 10.0 (should print integer)
    syscall

    li $v0 10
    syscall

Do you have a MIPS instruction-set reference? You might want to have a look at `cvt*.*`. — EOF, Mar 14 '16 at 20:59

Margaret Bloom · Accepted Answer · 2016-03-15T14:31:53.487

2

Disclaimer: I'm not an expert on MIPS arch.

As suggested in the comments, a quick lookup for MIPS FP reference gives the desired instruction: cvt.w.s.

.data
    five: .float 5.0
.text

#Convert five into an integer
la $t1, five
l.s $f12, ($t1)             #f12 = five
cvt.w.s $f0, $f12           #f0 = (int) five


#Print five
li $v0, 2
syscall

#Print (int)five
li $v0, 1
mfc1 $a0, $f0               #a0 = (int)five
syscall

#Exit
li $v0, 10
syscall

This will print

5.05

As there is no space between the 5.0 and the 5.

If you want to do it by hand, you can start from this answer.

edited Mar 15 '16 at 14:31

answered Mar 14 '16 at 21:23

Margaret Bloom

41,768
5
78
124

Thank you! That's exactly what I needed to see. I'll have to take a closer look at cvt. – DanteVFenris Mar 14 '16 at 21:45
The contents of a floating-point register can be moved to a GPR with `mfc1` (e.g. `mfc1 $a0, $f0`), which removes the need for the extra load and store to memory. – Michael Mar 15 '16 at 14:22
@Michael Super duper thanks! Those loads/stores were ugly. – Margaret Bloom Mar 15 '16 at 14:32

MIPS convert float into an integer

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