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No commits in common. "main" and "xe" have entirely different histories.
11 changed files with 1651 additions and 2348 deletions
10
Makefile
10
Makefile
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@ -2,11 +2,8 @@
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all : mandel.xex
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mandel.xex : mandel.o mandel-core.o tables.o atari-xex.cfg
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ld65 -C ./atari-xex.cfg --mapfile mandel.map -o $@ mandel.o mandel-core.o tables.o atari.lib
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mandel.s : mandel.c mandel.h
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cc65 -o $@ mandel.c
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mandel.xex : mandel.o tables.o
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ld65 -C ./atari-asm-xex.cfg -o $@ $+
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%.o : %.s
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ca65 -o $@ $<
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@ -16,7 +13,6 @@ tables.s : tables.js
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clean :
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rm -f tables.s
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rm -f mandel.s
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rm -f *.o
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rm -f *.xex
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rm -f mandel.map
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@ -1,28 +0,0 @@
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FEATURES {
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STARTADDRESS: default = $2E00;
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}
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SYMBOLS {
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__STARTADDRESS__: type = export, value = %S;
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}
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MEMORY {
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ZP: file = "", define = yes, start = $0082, size = $007E;
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MAIN: file = %O, define = yes, start = %S, size = $4000 - %S;
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# Keep $4000-7fff clear for expanded RAM access window
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TABLES: file = %O, define = yes, start = $8000, size = $a000 - $8000;
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# Keep $a000-$bfff clear for BASIC cartridge
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}
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FILES {
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%O: format = atari;
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}
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FORMATS {
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atari: runad = start;
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}
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SEGMENTS {
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ZEROPAGE: load = ZP, type = zp, optional = yes;
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EXTZP: load = ZP, type = zp, optional = yes; # to enable modules to be able to link to C and assembler programs
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CODE: load = MAIN, type = rw, define = yes;
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RODATA: load = MAIN, type = ro optional = yes;
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DATA: load = MAIN, type = rw optional = yes;
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BSS: load = MAIN, type = bss, optional = yes, define = yes;
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TABLES: load = TABLES, type = ro, optional = yes, align = 256;
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}
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@ -1,69 +0,0 @@
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# Sample linker configuration for C programs using the Atari binary file support.
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# Use with: cl65 -tatari -Catari-xex.cfg prog.c -o prog.xex
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FEATURES {
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STARTADDRESS: default = $8000;
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}
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SYMBOLS {
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__SYSTEM_CHECK__: type = import; # force inclusion of "system check" load chunk
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__STACKSIZE__: type = weak, value = $0800; # 2k stack
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__STARTADDRESS__: type = export, value = %S;
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__RESERVED_MEMORY__: type = weak, value = $0000;
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__SYSCHKHDR__: type = export, value = 0; # Disable system check header
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__SYSCHKTRL__: type = export, value = 0; # Disable system check trailer
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__TABLESEG_START__: type = weak, value = $2E00 + $0300;
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__TABLESEG_SIZE__: type = weak, value = 6 * $100;
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__BANKSY_START__: type = weak, value = $4000;
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__BANKSY_SIZE__: type = weak, value = $4000;
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__FRAMEBUFFER_START__: type = weak, value = $A000;
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}
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MEMORY {
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# Note -- $80 and $81 (LOMEM) appear to be reserved in ZP.
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ZP: file = "", define = yes, start = $0082, size = $007E;
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# "system check" load chunk
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SYSCHKCHNK: file = %O, start = $2E00, size = $0300;
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# Note $a000-$bfff is against the BASIC cartridge, may require booting with OPTION.
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TABLES: file = %O, define = yes, start = __TABLESEG_START__, size = __TABLESEG_SIZE__;
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# We reserve $4000-7fff for the bank-switch window.
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# In theory we could keep data and code here that we only use on 48k/64k systems.
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BANKSWITCH: file = "", define = yes, start = __BANKSY_START__, size = __BANKSY_SIZE__;
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# "main program" load chunk
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MAIN: file = %O, define = yes, start = %S, size = __FRAMEBUFFER_START__ - __STACKSIZE__ - __RESERVED_MEMORY__ - %S;
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}
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FILES {
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%O: format = atari;
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}
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FORMATS {
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atari: runad = start,
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initad = SYSCHKCHNK: __SYSTEM_CHECK__;
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}
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SEGMENTS {
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ZEROPAGE: load = ZP, type = zp;
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EXTZP: load = ZP, type = zp, optional = yes;
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SYSCHK: load = SYSCHKCHNK, type = rw, define = yes, optional = yes;
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TABLES: load = TABLES, type = ro, optional = yes, align = 256;
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BANKSWICH: load = BANKSWITCH, type = ro, optional = yes;
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STARTUP: load = MAIN, type = ro, define = yes;
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LOWBSS: load = MAIN, type = rw, optional = yes; # not zero initialized
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LOWCODE: load = MAIN, type = ro, define = yes, optional = yes;
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ONCE: load = MAIN, type = ro, optional = yes;
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CODE: load = MAIN, type = ro, define = yes;
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RODATA: load = MAIN, type = ro;
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DATA: load = MAIN, type = rw;
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INIT: load = MAIN, type = rw, optional = yes;
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BSS: load = MAIN, type = bss, define = yes;
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}
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FEATURES {
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CONDES: type = constructor,
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label = __CONSTRUCTOR_TABLE__,
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count = __CONSTRUCTOR_COUNT__,
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segment = ONCE;
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CONDES: type = destructor,
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label = __DESTRUCTOR_TABLE__,
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count = __DESTRUCTOR_COUNT__,
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segment = RODATA;
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CONDES: type = interruptor,
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label = __INTERRUPTOR_TABLE__,
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count = __INTERRUPTOR_COUNT__,
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segment = RODATA,
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import = __CALLIRQ__;
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}
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175
imul8xe.s
Normal file
175
imul8xe.s
Normal file
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@ -0,0 +1,175 @@
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FR0 = $d4 ; float48
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PORTB = $d301
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EXTENDED_RAM = $4000 ; 16KiB bank on the XE
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; lookup table for top byte -> PORTB value for bank-switch
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.align 256
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bankswitch:
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.repeat 256, i
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.byte ((i & $c0) >> 5) | $c1
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.endrepeat
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; 58-77 cycles
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; clobbers x, y, dest to dest + 3
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.macro imul8xe dest, arg1, arg2
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.local done
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.local output
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.local ptr
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output = dest
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ptr = dest + 2 ; scratch space assumed
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; bottom 14 bits except the LSB are the per-bank table index
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; add $4000 for the bank pointer
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lda arg1 ; 3 cyc
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and #$fe ; 2 cyc
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sta ptr ; 3 cyc
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lda arg2 ; 3 cyc
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and #$3f ; 2 cyc
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clc ; 2 cyc
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adc #$40 ; 2 cyc
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sta ptr + 1 ; 3 cyc
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; top 2 bits are the table bank selector
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ldx arg2 ; 3 cyc
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lda bank_switch,x ; 4 cyc
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sta PORTB ; 4 cyc
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; copy the entry into output
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ldy #0 ; 2 cyc
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lda (ptr),y ; 5 cyc
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sta output ; 3 cyc
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iny ; 2 cyc
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lda (ptr),y ; 5 cyc
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sta output+1 ; 3 cyc
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; note: we are not restoring memory to save 6 cycles!
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; this means those 16kb have to be switched back to base RAM
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; if we need to use them anywhere else
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;;; restore memory
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;;lda #$81 ; 2 cyc - disabled
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;;sta PORTB ; 4 cyc - disabled
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; check that 1 bit we skipped to fit into space
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lda arg1 ; 3 cyc
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and #1 ; 2 cyc
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beq done ; 2 cyc
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; add the second param one last time for the skipped bit
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clc ; 2 cyc
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lda arg2 ; 3 cyc
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adc output ; 3 cyc
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sta output ; 3 cyc
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lda #0 ; 2 cyc
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adc output+1 ; 3 cyc
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sta output+1 ; 3 cyc
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done:
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.endmacro
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.macro bank_switch bank
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lda #((bank << 1) | $c1)
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sta PORTB
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.endmacro
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proc imul8xe_init
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; go through the input set, in four 16KB chunks
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arg1 = FR1
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arg2 = FR2
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result = FR0
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lda #$00
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sta arg1
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sta arg2
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; $00 * $00 -> $3f * $ff
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bank_switch 0
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jsr imul8xe_init_section
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; $40 * $00 -> $7f * $ff
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bank_switch 1
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jsr imul8xe_init_section
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; $80 * $00 -> $bf * $ff
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bank_switch 2
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jsr imul8xe_init_section
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; $c0 * $00 -> $ff * $ff
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bank_switch 3
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jsr imul8xe_init_section
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rts
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endproc
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; Initialize a 16 KB chunk of the table
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; input: multipliers in temp
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; output: new multipliers in temp
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; clobbers: temp, temp2
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proc imul8xe_init_section
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arg1 = FR1
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arg2 = FR2
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result = FR0
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ptr = temp2
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lda #$00
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sta ptr
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lda #$40
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sta ptr + 1
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ldx #0
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ldy #0
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; outer loop: $00 -> $3f
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outer_loop:
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; reset result to 0
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lda #0
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sta result
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sta result + 1
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; inner loop: $00 -> $ff
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inner_loop:
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; copy result to data set
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lda result
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sta (ptr),y
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lda result + 1
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sta (ptr),y
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; result += 2 * arg2
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clc
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lda arg2
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adc result
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sta result
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lda #0
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adc result + 1
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sta result
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lda arg2
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adc result
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sta result
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lda #0
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adc result + 1
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sta result
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; inner loop check
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inc arg1
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inc arg1
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inc ptr
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inc ptr
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bne inner_loop
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; outer loop check
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inc arg2
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inc ptr + 1
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lda ptr + 1
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cmp #$40
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bne outer_loop
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rts
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endproc
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2181
mandel-core.s
2181
mandel-core.s
File diff suppressed because it is too large
Load diff
15
mandel.c
15
mandel.c
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@ -1,15 +0,0 @@
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/**
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* The UI and I/O wrapper for the Mandelbrot runner, in C.
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*
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* For the moment *all* logic is in mandel-core.s, I'm just
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* trying to get this to run within a cc65 environment.
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* Eventually just the inner loop fun will live in there.
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*/
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#include <stdlib.h>
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#include <stdio.h>
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#include "mandel.h"
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void main(void) {
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mandel_start();
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}
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4
mandel.h
4
mandel.h
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@ -1,4 +0,0 @@
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#include <inttypes.h>
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// From mandel-core.s:
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extern void mandel_start(void);
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26
readme.md
26
readme.md
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@ -14,37 +14,33 @@ Non-goals:
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Enjoy! I'll probably work on this off and on for the next few weeks until I've got it producing fractals.
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-- brooke, january 2023 - december 2024
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-- brooke, january 2023 - february 2024
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## Current state
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Basic rendering is functional, with interactive zoom/pan (+/-/arrows) and 6 preset viewports via the number keys.
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Basic rendering is functional, but no interactive behavior (zoom/pan) or benchmarking is done yet.
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The 16-bit signed integer multiplication takes two 16-bit inputs and emits one 32-bit output in the zero page, using the Atari OS ROM's floating point registers as workspaces. Inputs are clobbered.
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The 16-bit signed integer multiplication works; it takes two 16-bit inputs and emits one 32-bit output in the zero page, using the Atari OS ROM's floating point registers as workspaces. Inputs are clobbered.
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* 16-bit multiplies are decomposed into 4 8-bit unsigned multiplies and some addition
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* an optimized case for squares uses a table of 8-bit squares to reduce the number of 8-bit multiplication sub-ops
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* when expanded RAM is available as on 130XE, a 64KB 8-bit multiplication table accelerates the remaining multiplications
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* without expanded RAM, a table of half-squares is used to implement the algorithm from https://everything2.com/title/Fast+6502+multiplication
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The main loop is a basic add-and-shift, using 16-bit adds which requires flipping the sign of negative inputs (otherwise you'd have to add all those sign-extension bits). Runs in 470-780 cycles depending on input.
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The mandelbrot calculations are done using 3.13-precision fixed point numbers with 6.26-precision intermediates.
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The mandelbrot calculations are done using 4.12-precision fixed point numbers. It may be possible to squish this down to 3.13.
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Iterations are capped at 255.
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The pixels are run in a progressive layout to get the basic shape on screen faster.
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There is a running counter of ms/px using the vertical blank interrupts as a timer, used to track our progress. :D
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## Next steps
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There's a check for cycles in (zx,zy) output when in the 'lake'; if values repeat, they cannot escape. This is a big time saver in fractint.
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Add a running counter of ms/px using the vertical blank interrupts as a timer. This'll show how further work improves it!
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There's some cute color cycling.
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Check for cycles in (zx,zy) output when in the 'lake'; if values repeat, they cannot escape. This is a big time saver in fractint.
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I may be able to do a faster multiply using tables of squares for 8-bit component multiplication.
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(done)
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## Deps and build instructions
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I'm using `ca65` as a macro assembler, and have a Unix-style `Makefile` for building. Should work fairly easily on Linux and Mac. Might work on "raw" Windows but I use WSL for that.
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||||
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Currently produces a `.xex` executable, which can be booted up in common Atari emulators and some i/o devices.
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||||
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||||
## Todo
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||||
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||||
See ideas in `todo.md`.
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||||
|
|
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|||
12
tables.js
12
tables.js
|
|
@ -22,10 +22,7 @@ console.log(
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|||
.export mul_lobyte256
|
||||
.export mul_hibyte256
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||||
.export mul_hibyte512
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||||
.export sqr_lobyte
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||||
.export sqr_hibyte
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||||
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||||
; (i * i + 1) / 2 for the multiplier
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.align 256
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mul_lobyte256:
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||||
${db((i) => squares[i] & 0xff)}
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@ -38,13 +35,4 @@ ${db((i) => (squares[i] >> 8) & 0xff)}
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|||
mul_hibyte512:
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||||
${db((i) => (squares[i + 256] >> 8) & 0xff)}
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||||
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||||
; (i * i) for the plain squares
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||||
.align 256
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||||
sqr_lobyte:
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||||
${db((i) => (i * i) & 0xff)}
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||||
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||||
.align 256
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||||
sqr_hibyte:
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||||
${db((i) => ((i * i) >> 8) & 0xff)}
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||||
|
||||
`);
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||||
|
|
|
|||
17
todo.md
17
todo.md
|
|
@ -1,17 +0,0 @@
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|||
things to try:
|
||||
|
||||
* fix status bar to show elapsed time, per-iter time, per-pixel iter count
|
||||
|
||||
* 'turbo' mode disabling graphics in full or part
|
||||
|
||||
* patch the entire expanded-ram imul8xe on top of imul8 to avoid the 3-cycle thunk penalty :D
|
||||
|
||||
* maybe clean up the load/layout of the big mul table
|
||||
|
||||
* consider alternate lookup tables in the top 16KB under ROM
|
||||
|
||||
* y-axis mirror optimization
|
||||
|
||||
* extract viewport for display & re-input via keyboard
|
||||
|
||||
* fujinet screenshot/viewport uploader
|
||||
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