;* ======================================================================== *; ;* The routines and data in this file (memset.asm) are dedicated to the *; ;* public domain via the Creative Commons CC0 v1.0 license by its author, *; ;* Joseph Zbiciak. *; ;* *; ;* https://creativecommons.org/publicdomain/zero/1.0/ *; ;* ======================================================================== *; ;; ======================================================================== ;; ;; MEMSET Fill array with value ;; ;; MEMSET.1 Alternate entry point ;; ;; ;; ;; AUTHOR ;; ;; Joseph Zbiciak ;; ;; ;; ;; REVISION HISTORY ;; ;; 08-Sep-2001 Initial Revision ;; ;; ;; ;; INPUTS for MEMSET ;; ;; R5 Pointer to invocation record, followed by return address. ;; ;; Pointer to destination 1 DECLE ;; ;; Value to fill with 1 DECLE ;; ;; Length 1 DECLE ;; ;; ;; ;; INPUTS for MEMSET.1 ;; ;; R5 Return address ;; ;; R4 Pointer to destination ;; ;; R1 Value to fill with ;; ;; R0 Length ;; ;; ;; ;; OUTPUTS ;; ;; R0 Zeroed ;; ;; R1 Fill value (unmodified) ;; ;; R4 Points one element beyond destination array ;; ;; R5 Zeroed ;; ;; ;; ;; TECHNIQUES ;; ;; Unrolled 8x for speed. ;; ;; Not-unrolled loop handles length % 8 != 0. ;; ;; ;; ;; CODESIZE ;; ;; 29 words ;; ;; ;; ;; CYCLES ;; ;; Not yet characterized. ;; ;; ======================================================================== ;; MEMSET PROC MVI@ R5, R4 ; 8 Destination array MVI@ R5, R1 ; 8 Fill value MVI@ R5, R0 ; 8 Length @@1: PSHR R5 ; 9 Alternate entry point MOVR R0, R5 ; 6 \ ANDI #7, R5 ; 8 |-- Handle length % 8 iters, BEQ @@l8_init ; 7/9 / if there are any. ;---- ; 54 Fallthru case ; 56 Branch taken @@loop_1: MVO@ R1, R4 ; 9 \ DECR R5 ; 6 |-- Store one value at a time. BNEQ @@loop_1 ; 9/7 / ;---- ; 24*k - 2 @@l8_init: SLR R0, 2 ; 8 \ SLR R0, 1 ; 6 |-- Divide trip count by 8. BEQ @@done ; 7/9 / Abort if it goes to 0. ;---- ; 21 Fallthru case @@loop_8: MVO@ R1, R4 ; 9 \ MVO@ R1, R4 ; 9 |__ Store four elements MVO@ R1, R4 ; 9 | MVO@ R1, R4 ; 9 / DECR R0 ; 6 (Interruptible) MVO@ R1, R4 ; 9 \ MVO@ R1, R4 ; 9 |__ Store four more elements MVO@ R1, R4 ; 9 | MVO@ R1, R4 ; 9 / BNEQ @@loop_8 ; 9/7 Iterate length/8 times ;---- ; 87*k - 2 @@done: PULR PC ; 11 Return ENDP ;; ======================================================================== ;; ;; End of File: memset.asm ;; ;; ======================================================================== ;;