Intel 64 and IA-32 Architectures Software Developers Manual Volume 2B, Instruction Set Reference, N-Z

Vol. 2B 4-355
INSTRUCTION SET REFERENCE, N-Z
SUBSS—Subtract Scalar Single-Precision Floating-Point Values
Description
Subtracts the low single-precision floating-point value in the source operand (second
operand) from the low single-precision floating-point value in the destination
operand (first operand), and stores the single-precision floating-point result in the
destination operand. The source operand can be an XMM register or a 32-bit memory
location. The destination operand is an XMM register. The three high-order double-
words of the destination operand remain unchanged. See Figure 10-6 in the Intel
®
64 and IA-32 Architectures Software Developer’s Manual, Volume 1, for an illustra-
tion of a scalar single-precision floating-point operation.
In 64-bit mode, using a REX prefix in the form of REX.R permits this instruction to
access additional registers (XMM8-XMM15).
Operation
DEST[31:0] ← DEST[31:0] − SRC[31:0];
(* DEST[127:96] unchanged *)
Intel C/C++ Compiler Intrinsic Equivalent
SUBSS __m128 _mm_sub_ss(__m128 a, __m128 b)
SIMD Floating-Point Exceptions
Overflow, Underflow, Invalid, Precision, Denormal.
Protected Mode Exceptions
#GP(0) For an illegal memory operand effective address in the CS, DS,
ES, FS or GS segments.
#SS(0) For an illegal address in the SS segment.
#PF(fault-code) For a page fault.
#NM If CR0.TS[bit 3] = 1.
#XM If an unmasked SIMD floating-point exception and CR4.OSXM-
MEXCPT[bit 10] = 1.
Opcode Instruction
64-Bit
Mode
Compat/
Leg
Mode Description
F3 0F 5C /r SUBSS xmm1,
xmm2/m32
Valid Valid Subtract the lower single-precision
floating-point values in
xmm2/m32 from xmm1.