CPSC 355 Lecture Notes - Lecture 13: Extended Precision, Subtraction, Bit Field

• School: University of Calgary
• Department: Computer Science
• Course: CPSC 355
• Professor: Leonard Manzara

Document Summary

Cpsc 355 - lecture 13 oct 12th. Bitfield insert: form (32-bit): bfi wd, wn, #lsb, #width. #width: number of bits in the bitfield: source bitfield occupies bits 0 to (width -1) in wn, bits lsb to (lsb + width 1) in wd are replaced by the source bitfield, eg: // (cid:1004)(cid:1004)(cid:1004)(cid:1004) (cid:1004)(cid:1004)(cid:1004)(cid:1004) (cid:1005)(cid:1004)(cid:1005)(cid:1004) 1010 mov w20, 0xaa mov w19, 0xffffffff // (cid:1005)(cid:1005)(cid:1005)(cid:1005) (cid:1005)(cid:1005)(cid:1005)(cid:1005) (cid:1005)(cid:1005)(cid:1005)(cid:1005) (cid:1005)(cid:1005)(cid:1005)(cid:1005) // (cid:1005)(cid:1005)(cid:1005)(cid:1005) (cid:1005)(cid:1005)(cid:1005)(cid:1004) 1010 1111 bfi w19, w20, 4, 5. Unsigned bitfield insert in zero (ubfiz: similar to bfi, except that wd is zeroed first. Signed bitfield insert in zero (sbfiz: similar to ubfiz, except that bits on left are sign extended. Bitfield extract and insert low: form (32-bit) bfxil wd, wn, #lsb, #width. #width: number of bits in the bitfield: source bitfield is bits lsb to (lsb + width 1) in wn, bits 0 to (width 1) in wd are replaced by the source bitfield.