Speculative register file read suppression

Apparatus comprising:

• architected register file means for storing committed register values within architected registers;
• speculative register file means for storing uncommitted register values within speculative registers;
• speculative register allocation means for allocating in order within an allocation sequence from a tail point within said allocation sequence a speculative register to serve as an operand destinations;
• and
• read suppression means:
• (i) for maintaining a boundary pointer for a type of register value to a boundary speculative register within said allocation sequence having a location within said allocation sequence such that no speculative register more recently allocated within said allocation sequence than said boundary speculative register can contain a valid register value of said type of register value;
• and
• (ii) for suppressing a read to provide a source operand value of a speculative register within a read-suppression region of said allocation sequence delimited by said tail point and said boundary pointer.

A method comprising the steps of:

• storing committed register values within architected registers;
• storing uncommitted register values within speculative registers;
• allocating in order within an allocation sequence from a tail point within said allocation sequence a speculative register to serve as an operand destinations;
• maintaining a boundary pointer for a type of register value to a boundary speculative register within said allocation sequence having a location within said allocation sequence such that no speculative register more recently allocated within said allocation sequence than said boundary speculative register can contain a valid register value of said type of register value;
• and
• suppressing a read to provide a source operand value of a speculative register within a read-suppression region of said allocation sequence delimited by said tail point and said boundary pointer.