Chapter 6

VHDL Language Support

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"

• "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 the VHDL attribute syntax, see the "VHDL Attribute Syntax" section