x86 Instruction Set Reference

# CVTTPS2PI

# Convert with Truncation Packed Single-Precision Floating-Point Values to Packed Doubleword Integers

Opcode Mnemonic Description
0F 2C /r CVTTPS2PI mm, xmm/m64 Convert two single-precision floating-point values from xmm/m64 to two signed doubleword signed integers in mm using truncation.

# Description

Converts two packed single-precision floating-point values in the source operand (second operand) to two packed signed doubleword integers in the destination operand (first operand).

The source operand can be an XMM register or a 64-bit memory location. The destination operand is an MMX technology register. When the source operand is an XMM register, the two single-precision floating-point values are contained in the low quadword of the register.

When a conversion is inexact, a truncated (round toward zero) result is returned. If a converted result is larger than the maximum signed doubleword integer, the floating-point invalid exception is raised, and if this exception is masked, the indefinite integer value (80000000H) is returned.

This instruction causes a transition from x87 FPU to MMX technology operation (that is, the x87 FPU top-of-stack pointer is set to 0 and the x87 FPU tag word is set to all 0s [valid]). If this instruction is executed while an x87 FPU floating-point exception is pending, the exception is handled before the CVTTPS2PI instruction is executed.

# Operation

Destination[0..31] = ConvertFloatToIntegerTruncate(Source[0..31]);
Destination[32..63] = ConvertFloatToIntegerTruncate(Source[32..63]);
1
2
3

# SIMD Floating-Point Exceptions

Invalid, Precision.

# Protected Mode Exceptions
#GP(0) For an illegal memory operand effective address in the CS, DS, ES, FS or GS segments.
#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.
#MF If there is a pending x87 FPU exception.
#NM If TS in CR0 is set.
#XM If an unmasked SIMD floating-point exception and OSXMMEXCPT in CR4 is 1.
#UD If an unmasked SIMD floating-point exception and OSXMMEXCPT in CR4 is 0. If EM in CR0 is set. If OSFXSR in CR4 is 0. If CPUID feature flag SSE is 0.

# Real-Address Mode Exceptions
GP(0) If any part of the operand lies outside the effective address space from 0 to FFFFH.
GP(0) If any part of the operand lies outside the effective address space from 0 to FFFFH.
#NM If TS in CR0 is set.
#MF If there is a pending x87 FPU exception.
#XM If an unmasked SIMD floating-point exception and OSXMMEXCPT in CR4 is 1.

# Virtual-8086 Mode Exceptions

Same exceptions as in Real Address Mode
#PF(fault-code) For a page fault.
#PF(fault-code) For a page fault.
Instruction Latency Throughput Execution Unit
CPUID 0F3n/0F2n/069n 0F3n/0F2n/069n 0F2n
CVTTPS2PI mm, xmm 8/7/3 2/2/1 FP_ADD MMX_ALU

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