Memcpy.asm
Revision as of 08:57, 4 December 2010 by Mr z (talk | contribs) (Protected "Memcpy.asm" ([edit=autoconfirmed] (indefinite) [move=autoconfirmed] (indefinite)))
Functions Provided
Entry point | Function provided | Notes |
---|---|---|
MEMCPY | Copy a block of memory | Source, destination and length fixed in ROM. |
MEMCPY.1 | Source, destination and length in registers. |
See source code below for calling convention.
Examples
(todo... please contribute!)
Notes
Source Code
;* ======================================================================== *; ;* These routines are placed into the public domain by their author. All *; ;* copyright rights are hereby relinquished on the routines and data in *; ;* this file. -- Joseph Zbiciak, 2008 *; ;* ======================================================================== *; ;; ======================================================================== ;; ;; MEMCPY Copy one array to another ;; ;; MEMCPY.1 Alternate entry point ;; ;; ;; ;; AUTHOR ;; ;; Joseph Zbiciak <intvnut AT gmail.com> ;; ;; ;; ;; REVISION HISTORY ;; ;; 08-Sep-2001 Initial Revision ;; ;; ;; ;; INPUTS for MEMCPY ;; ;; R5 Pointer to invocation record, followed by return address. ;; ;; Pointer to destination 1 DECLE ;; ;; Pointer to source 1 DECLE ;; ;; Length 1 DECLE ;; ;; ;; ;; INPUTS for MEMCPY.1 ;; ;; R5 Return address ;; ;; R4 Pointer to destination ;; ;; R1 Pointer to source ;; ;; R0 Length ;; ;; ;; ;; OUTPUTS ;; ;; R0 $FFFF ;; ;; R1 Last element copied ;; ;; R4 Points one element beyond destination array ;; ;; R5 Points one element beyond source array ;; ;; ;; ;; TECHNIQUES ;; ;; Unrolled 8x for speed. ;; ;; Special dispatch handles length % 8 != 0. ;; ;; ;; ;; CODESIZE ;; ;; 35 words ;; ;; ;; ;; CYCLES ;; ;; Not yet characterized. ;; ;; ======================================================================== ;; MEMCPY PROC MVI@ R5, R4 ; 8 Destination array MVI@ R5, R1 ; 8 Source array MVI@ R5, R0 ; 8 Length @@1: PSHR R5 ; 9 Alternate entry point MOVR R1, R5 ; 6 Use auto-incr pointer MOVR R0, R1 ; 6 Copy array length SLR R0, 2 ; 8 \___ Find floor(length / 8) SLR R0, 1 ; 6 / ANDI #7, R1 ; 8 \ ADDR R1, R1 ; 6 |__ Find address to jump to for SUBI #@@end, R1 ; 8 | first iteration, to handle NEGR R1 ; 6 / length % 8. MOVR R1, PC ; 6 Jump into copy loop. @@loop: MVI@ R5, R1 ; 8 MVO@ R1, R4 ; 9 MVI@ R5, R1 ; 8 MVO@ R1, R4 ; 9 MVI@ R5, R1 ; 8 MVO@ R1, R4 ; 9 MVI@ R5, R1 ; 8 MVO@ R1, R4 ; 9 MVI@ R5, R1 ; 8 MVO@ R1, R4 ; 9 MVI@ R5, R1 ; 8 MVO@ R1, R4 ; 9 MVI@ R5, R1 ; 8 MVO@ R1, R4 ; 9 MVI@ R5, R1 ; 8 MVO@ R1, R4 ; 9 @@end: DECR R0 ; 6 BPL @@loop ; 9/7 Iterate floor(length/8) + 1 times ;---- ; 151*k - 2 @@done: PULR PC ; 11 Return ENDP ;; ======================================================================== ;; ;; End of File: memcpy.asm ;; ;; ======================================================================== ;;