add alternate version of memset (probably slower (only for testing))

This commit is contained in:
hugova 2025-07-15 22:33:19 +02:00
parent 44ac08950a
commit b8df5cb84b
4 changed files with 125 additions and 16 deletions

View file

@ -8,14 +8,14 @@
t2 = $E1
X_math = radius
Y_math = $E2
;; E9 - EA is used by pixel.inc
byte_to_paint_qaa = $E8
byte_to_paint_qcb = $E3
byte_to_paint_qca = $E4
byte_to_paint_qdb = $E5
byte_to_paint_qaa = $E3
byte_to_paint_qcb = $E4
byte_to_paint_qca = $E5
byte_to_paint_qdb = $E6
btp_mem_pos_qaa = btp_mem_pos
btp_mem_pos_qcb = $E6 ; 16bit value (uses E7)
btp_mem_pos_qcb = $E7 ; 16bit value (uses E8)
; E9 - EA is used by pixel.inc
btp_mem_pos_qdb = $EB ; 16bit value (uses EC)
btp_mem_pos_qda = $ED ; 16bit value (uses EE)
btp_mem_pos_qab = $D0 ; 16bit value (uses D1)

View file

@ -4,3 +4,8 @@
A_start = $D0 ; 16-bit value (uses D1)
B_start = $D2 ; 16-bit value (uses D3)
length = $D4 ; 16-bit value (uses D5), this is the number of bytes
RTS_pointer = $D6 ; 16-bit value (uses D7)
data_to_write = $D8
length_copy = $d9 ; 16-bit vale (uses da)
instruction_backup = $db

View file

@ -18,6 +18,8 @@ big_set: ;sets $ff of memory
DEY
.endrepeat
STA (A_start), Y ; dont forget Y =0
NOP
NOP
big_set_end:
;;set all hole $ff memory chunks!
INC A_start + 1
@ -26,15 +28,46 @@ big_set_end:
JMP big_set
;;sets the rest of the memory
;; note that this can use code above (smc) or the same method. may implement later.
small_set:
LDY length
small_set_loop:
STA (A_start), Y
DEY
BNE small_set_loop
STA (A_start), Y
STA data_to_write
LDA length
STA length_copy
;; calculate rts-position
LDA #$00
STA length + 1
;; 4 bytes = STA DEY NOP = seting 1 byte of memory.
;; So we need to calculate: length*4
Mult_16 length, length + 1
Add_16 length, length + 1, length_copy, #$00
;; Now RTS_pointer = length*4 + big_set_label
CLC
LDA #<big_set
ADC length
STA RTS_pointer
LDA #>big_set
ADC length + 1
STA RTS_pointer + 1
;; read data we will change to RTS
LDY #$00
LDA (RTS_pointer), Y
STA instruction_backup
;; set RTS in big_set
LDA #$60
STA (RTS_pointer), Y
;; JSR to modified big_set
LDY length_copy
DEY ; because we want to count to Y=0 :)
LDA data_to_write
JSR big_set
;; revert changes
LDY #$00
LDA instruction_backup
STA (RTS_pointer), Y
RTS
.endproc

View file

@ -0,0 +1,71 @@
;;; -*- Mode: asm; indent-tabs-mode: t; tab-width: 8 -*-
;; Sets memory in 'A'-registry to all addresses from 'A_start' until 'A_start' + 'length'
;; Modifies A, X and A_start
.proc memset
.include "mem.inc"
;; big_set sets the memory in $ff chunks.
;; skipp if length >= $ff
LDX length +1
BNE big_set
JMP small_set
big_set: ;sets $ff of memory
;; Y value do not matter, will go through all anyway!
.repeat $ff
STA (A_start), Y
DEY
.endrepeat
STA (A_start), Y ; dont forget Y =0
big_set_end:
;;set all hole $ff memory chunks!
INC A_start + 1
DEX ;; length +1 --
BEQ small_set
JMP big_set
small_set:
STA data_to_write
LDA length
STA length_copy
;; calculate rts-position
LDA #$00
STA length + 1
;; 4 bytes = STA DEY NOP = seting 1 byte of memory.
;; So we need to calculate: length*4
Mult_16 length, length + 1
Add_16 length, length + 1, length_copy, #$00
;; Now RTS_pointer = length*4 + big_set_label
CLC
LDA #<big_set
ADC length
STA RTS_pointer
LDA #>big_set
ADC length + 1
STA RTS_pointer + 1
;; read data we will change to RTS
LDY #$00
LDA (RTS_pointer), Y
STA instruction_backup
;; set RTS in big_set
LDA #$60
STA (RTS_pointer), Y
;; JSR to modified big_set
LDY length_copy
DEY ; because we want to count to Y=0 :)
LDA data_to_write
JSR big_set
;; revert changes
LDY #$00
LDA instruction_backup
STA (RTS_pointer), Y
RTS
.endproc