mirror of
https://github.com/irmen/prog8.git
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132 lines
5.3 KiB
Lua
132 lines
5.3 KiB
Lua
; Experimental Vera FX support.
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; Docs:
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; https://github.com/X16Community/x16-docs/blob/master/VERA%20FX%20Reference.md
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; https://docs.google.com/document/d/1q34uWOiM3Be2pnaHRVgSdHySI-qsiQWPTo_gfE54PTg/edit
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verafx {
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%option no_symbol_prefixing
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sub available() -> bool {
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; returns true if Vera FX is available (Vera V0.3.1 or later), false if not.
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cx16.r1L = 0
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cx16.r0L = cx16.VERA_CTRL
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cx16.VERA_CTRL = $7e
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if cx16.VERA_DC_VER0 == $56 {
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; Vera version number is valid.
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; Vera fx is available on Vera version 0.3.1 and later,
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; so no need to even check VERA_DC_VER1, which contains 0 (or higher)
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cx16.r1L = mkword(cx16.VERA_DC_VER2, cx16.VERA_DC_VER3) >= $0301
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}
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cx16.VERA_CTRL = cx16.r0L
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return cx16.r1L
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}
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sub clear(ubyte vbank, uword vaddr, ubyte data, uword amountof32bits) {
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; use cached 4-byte write to quickly clear a portion of the video memory to a given byte value
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; this routine is around 3 times faster as gfx2.clear_screen()
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cx16.VERA_CTRL = 0
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cx16.VERA_ADDR_H = vbank | %00110000 ; 4-byte increment
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cx16.VERA_ADDR_M = msb(vaddr)
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cx16.VERA_ADDR_L = lsb(vaddr)
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cx16.VERA_CTRL = 6<<1 ; dcsel = 6, fill the 32 bits cache
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cx16.VERA_FX_CACHE_L = data
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cx16.VERA_FX_CACHE_M = data
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cx16.VERA_FX_CACHE_H = data
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cx16.VERA_FX_CACHE_U = data
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cx16.VERA_CTRL = 2<<1 ; dcsel = 2
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cx16.VERA_FX_MULT = 0
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cx16.VERA_FX_CTRL = %01000000 ; cache write enable
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if (amountof32bits & %1111110000000011) == 0 {
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repeat lsb(amountof32bits >> 2)
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unroll 4 cx16.VERA_DATA0=0 ; write 4*4 bytes at a time, unrolled
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}
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else if (amountof32bits & %1111111000000001) == 0 {
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repeat lsb(amountof32bits >> 1)
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unroll 2 cx16.VERA_DATA0=0 ; write 2*4 bytes at a time, unrolled
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}
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else if (lsb(amountof32bits) & 3) == 0 {
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repeat amountof32bits >> 2
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unroll 4 cx16.VERA_DATA0=0 ; write 4*4 bytes at a time, unrolled
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}
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else if (lsb(amountof32bits) & 1) == 0 {
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repeat amountof32bits >> 1
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unroll 2 cx16.VERA_DATA0=0 ; write 2*4 bytes at a time, unrolled
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}
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else {
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repeat amountof32bits
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cx16.VERA_DATA0=0 ; write 4 bytes at a time
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}
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cx16.VERA_FX_CTRL = 0 ; cache write disable
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cx16.VERA_CTRL = 0
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}
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; unsigned multiplication just passes the values as signed to muls
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; if you do this yourself in your call to muls, it will save a few instructions.
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sub mult(uword value1, uword value2) -> uword {
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; Returns the lower 16 bits of the 32 bits result,
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; the upper 16 bits are stored in cx16.r0 so you can access those separately.
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; It's not part of the subroutine's signature to avoid awkward use of multiple returnvalues.
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return muls(value1 as word, value2 as word) as uword
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}
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asmsub muls(word value1 @R0, word value2 @R1) clobbers(X) -> word @AY {
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; Returns the lower 16 bits of the 32 bits result in AY,
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; the upper 16 bits are stored in cx16.r0 so you can access those separately.
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; It's not part of the subroutine's signature to avoid awkward use of multiple returnvalues.
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%asm {{
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lda #(2 << 1)
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sta cx16.VERA_CTRL ; $9F25
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stz cx16.VERA_FX_CTRL ; $9F29 (mainly to reset Addr1 Mode to 0)
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lda #%00010000
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sta cx16.VERA_FX_MULT ; $9F2C
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lda #(6 << 1)
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sta cx16.VERA_CTRL ; $9F25
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lda cx16.r0
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ldy cx16.r0+1
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sta cx16.VERA_FX_CACHE_L ; $9F29
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sty cx16.VERA_FX_CACHE_M ; $9F2A
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lda cx16.r1
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ldy cx16.r1+1
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sta cx16.VERA_FX_CACHE_H ; $9F2B
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sty cx16.VERA_FX_CACHE_U ; $9F2C
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lda cx16.VERA_FX_ACCUM_RESET ; $9F29 (DCSEL=6)
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; Set the ADDR0 pointer to $1f9bc and write our multiplication result there
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; (these are the 4 bytes just before the PSG registers start)
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lda #(2 << 1)
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sta cx16.VERA_CTRL
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lda #%01000000 ; Cache Write Enable
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sta cx16.VERA_FX_CTRL
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lda #$bc
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sta cx16.VERA_ADDR_L
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lda #$f9
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sta cx16.VERA_ADDR_M
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lda #$01
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sta cx16.VERA_ADDR_H ; no increment
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stz cx16.VERA_DATA0 ; multiply and write out result
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lda #%00010001 ; $01 with Increment 1
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sta cx16.VERA_ADDR_H ; so we can read out the result
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lda cx16.VERA_DATA0
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ldy cx16.VERA_DATA0
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ldx cx16.VERA_DATA0 ; store the upper 16 bits of the result in r0
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stx cx16.r0
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ldx cx16.VERA_DATA0
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stx cx16.r0+1
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stz cx16.VERA_FX_CTRL ; Cache write disable
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stz cx16.VERA_CTRL ; reset DCSEL
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rts
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}}
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}
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sub transparency(bool enable) {
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cx16.VERA_CTRL = 2<<1 ; dcsel = 2
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if enable
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cx16.VERA_FX_CTRL |= %10000000
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else
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cx16.VERA_FX_CTRL &= %01111111
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cx16.VERA_CTRL = 0
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}
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}
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