Xilinx Synthesis Technology User Guide

VHDL Language Support
Chapter 6
This chapter explains how VHDL is supported for XST. The chapter
provides details on the VHDL language, supported constructs, and
synthesis options in relationship to XST. The sections in this chapter
are as follows:
• “Introduction”
• “Data Types in VHDL”
• “Record Types”
• “Objects in VHDL”
• “Operators”
• “Entity and Architecture Descriptions”
• “Combinatorial Circuits”
• “Sequential Circuits”
• “Functions and Procedures”
• “Packages”
• “VHDL Language Support”
• “VHDL Reserved Words”
For a complete specification of VHDL, refer to the IEEE VHDL
Language Reference Manual.
For a detailed description of supported design constraints, refer to
the “Design Constraints” chapter. For a description of VHDL
attribute syntax, see the “Command Line Options” section of the
“Design Constraints” chapter.an XST
XST User Guide 6-1