Floating Point Instructions

The MIPS has a floating point coprocessor (numbered 1) that operates on single precision (32-bit) and double precision (64-bit) floating point numbers. This coprocessor has its own registers which are numbered $f0-$f31. Because these registers are only 32-bits wide two of them are required to hold doubles. To simplify matters floating point operations only use even-numbered registers--including instructions that operate on single floats.

Values are moved in or out of these registers a word (32-bits) at a time by lwc1 swc1 mtc1 and mfc1 instructions described above or by the l.s l.d s.s and s.d pseudoinstructions described below. The flag set by floating point comparison operations is read by the CPU with its bc1t and bc1f instructions.

In all instructions below FRdest FRsrc1 FRsrc2 and FRsrc are floating point registers (e.g. $f2).

abs.d FRdest FRsrcFloating Point Absolute Value Double
abs.s FRdest FRsrcFloating Point Absolute Value Single
Compute the absolute value of the floating float double (single) in register FRsrc and put it in register FRdest.

add.d FRdest FRsrc1 FRsrc2Floating Point Addition Double
add.s FRdest FRsrc1 FRsrc2Floating Point Addition Single
Compute the sum of the floating float doubles (singles) in registers FRsrc1 and FRsrc2 and put it in register FRdest.

c.eq.d FRsrc1 FRsrc2Compare Equal Double
c.eq.s FRsrc1 FRsrc2Compare Equal Single
Compare the floating point double in register FRsrc1 against the one in FRsrc2 and set the floating point condition flag true if they are equal.

c.le.d FRsrc1 FRsrc2Compare Less Than Equal Double
c.le.s FRsrc1 FRsrc2Compare Less Than Equal Single
Compare the floating point double in register FRsrc1 against the one in FRsrc2 and set the floating point condition flag true if the first is less than or equal to the second.

c.lt.d FRsrc1 FRsrc2Compare Less Than Double
c.lt.s FRsrc1 FRsrc2Compare Less Than Single
Compare the floating point double in register FRsrc1 against the one in FRsrc2 and set the condition flag true if the first is less than the second.

cvt.d.s FRdest FRsrcConvert Single to Double
cvt.d.w FRdest FRsrcConvert Integer to Double
Convert the single precision floating point number or integer in register FRsrc to a double precision number and put it in register FRdest.

cvt.s.d FRdest FRsrcConvert Double to Single
cvt.s.w FRdest FRsrcConvert Integer to Single
Convert the double precision floating point number or integer in register FRsrc to a single precision number and put it in register FRdest.

cvt.w.d FRdest FRsrcConvert Double to Integer
cvt.w.s FRdest FRsrcConvert Single to Integer
Convert the double or single precision floating point number in register FRsrc to an integer and put it in register FRdest.

div.d FRdest FRsrc1 FRsrc2Floating Point Divide Double
div.s FRdest FRsrc1 FRsrc2Floating Point Divide Single
Compute the quotient of the floating float doubles (singles) in registers FRsrc1 and FRsrc2 and put it in register FRdest.

l.d FRdest addressLoad Floating Point Double ${}^{\dagger}$
l.s FRdest addressLoad Floating Point Single ${}^{\dagger}$
Load the floating float double (single) at address into register FRdest.

mov.d FRdest FRsrcMove Floating Point Double
mov.s FRdest FRsrcMove Floating Point Single
Move the floating float double (single) from register FRsrc to register FRdest.

mul.d FRdest FRsrc1 FRsrc2Floating Point Multiply Double
mul.s FRdest FRsrc1 FRsrc2Floating Point Multiply Single
Compute the product of the floating float doubles (singles) in registers FRsrc1 and FRsrc2 and put it in register FRdest.

neg.d FRdest FRsrcNegate Double
neg.s FRdest FRsrcNegate Single
Negate the floating point double (single) in register FRsrc and put it in register FRdest.

s.d FRdest addressStore Floating Point Double ${}^{\dagger}$
s.s FRdest addressStore Floating Point Single ${}^{\dagger}$
Store the floating float double (single) in register FRdest at address.

sub.d FRdest FRsrc1 FRsrc2Floating Point Subtract Double
sub.s FRdest FRsrc1 FRsrc2Floating Point Subtract Single
Compute the difference of the floating float doubles (singles) in registers FRsrc1 and FRsrc2 and put it in register FRdest.