| /* SPDX-License-Identifier: GPL-2.0 */ |
| * arch/alpha/lib/ev67-strlen.S |
| * 21264 version by Rick Gorton <rick.gorton@alpha-processor.com> |
| * Finds length of a 0-terminated string. Optimized for the |
| * - memory accessed as aligned quadwords only |
| * - uses bcmpge to compare 8 bytes in parallel |
| * Much of the information about 21264 scheduling/coding comes from: |
| * Compiler Writer's Guide for the Alpha 21264 |
| * abbreviated as 'CWG' in other comments here |
| * ftp.digital.com/pub/Digital/info/semiconductor/literature/dsc-library.html |
| * U - upper subcluster; U0 - subcluster U0; U1 - subcluster U1 |
| * L - lower subcluster; L0 - subcluster L0; L1 - subcluster L1 |
| ldq_u $1, 0($16) # L : load first quadword ($16 may be misaligned) |
| cmpbge $31, $1, $2 # E : $2 <- bitmask: bit i == 1 <==> i-th byte == 0 |
| $loop: ldq $1, 8($0) # L : |
| addq $0, 8, $0 # E : addr += 8 |