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, FRsrc

Floating Point Absolute Value Double

abs.s FRdest, FRsrc

Floating 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, FRsrc2

Floating Point Addition Double

add.s FRdest, FRsrc1, FRsrc2

Floating 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, FRsrc2

Compare Equal Double

c.eq.s FRsrc1, FRsrc2

Compare 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, FRsrc2

Compare Less Than Equal Double

c.le.s FRsrc1, FRsrc2

Compare 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, FRsrc2

Compare Less Than Double

c.lt.s FRsrc1, FRsrc2

Compare 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, FRsrc

Convert Single to Double

cvt.d.w FRdest, FRsrc

Convert 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, FRsrc

Convert Double to Single

cvt.s.w FRdest, FRsrc

Convert 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, FRsrc

Convert Double to Integer

cvt.w.s FRdest, FRsrc

Convert 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, FRsrc2

Floating Point Divide Double

div.s FRdest, FRsrc1, FRsrc2

Floating 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, address

Load Floating Point Double

l.s FRdest, address

Load Floating Point Single

Load the floating float double (single) at address into register FRdest.

mov.d FRdest, FRsrc

Move Floating Point Double

mov.s FRdest, FRsrc

Move Floating Point Single

Move the floating float double (single) from register FRsrc to register FRdest.

mul.d FRdest, FRsrc1, FRsrc2

Floating Point Multiply Double

mul.s FRdest, FRsrc1, FRsrc2

Floating 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, FRsrc

Negate Double

neg.s FRdest, FRsrc

Negate Single

Negate the floating point double (single) in register FRsrc and put it in register FRdest.

s.d FRdest, address

Store Floating Point Double

s.s FRdest, address

Store Floating Point Single

Store the floating float double (single) in register FRdest at address.

sub.d FRdest, FRsrc1, FRsrc2

Floating Point Subtract Double

sub.s FRdest, FRsrc1, FRsrc2

Floating Point Subtract Single

Compute the difference of the floating float doubles (singles) in registers FRsrc1 and FRsrc2 and put it in register FRdest.