prog8/compiler/res/prog8lib/cx16/verafx.p8

196 lines
7.8 KiB
Lua

; Partial Vera FX support:
; - fast 32 bit cached writes (clear, copy)
; - transparent write setting
; - hardware 16 bits multiplications
;
; Docs:
; https://github.com/X16Community/x16-docs/blob/fb63156cca2d6de98be0577aacbe4ddef458f896/X16%20Reference%20-%2010%20-%20VERA%20FX%20Reference.md
; https://docs.google.com/document/d/1q34uWOiM3Be2pnaHRVgSdHySI-qsiQWPTo_gfE54PTg
verafx {
%option no_symbol_prefixing, ignore_unused
sub available() -> bool {
; returns true if Vera FX is available (Vera V0.3.1 or later), false if not.
cx16.r0L = cx16.VERA_CTRL
cx16.r0H = 0
cx16.VERA_CTRL = $7e
if cx16.VERA_DC_VER0 == $56 {
; Vera version number is valid. Vera fx is available on Vera version 0.3.1 and later.
if cx16.VERA_DC_VER1>0
cx16.r0H = 1
else
cx16.r0H = mkword(cx16.VERA_DC_VER2, cx16.VERA_DC_VER3) >= $0301 as ubyte
}
cx16.VERA_CTRL = cx16.r0L
return cx16.r0H as bool
}
sub clear(ubyte vbank, uword vaddr, ubyte data, uword num_longwords) {
; use cached 4-byte write to quickly clear a portion of the video memory to a given byte value
; this routine is around 3 times faster as gfx_hires4/gfx_lores.clear_screen()
cx16.VERA_CTRL = 0
cx16.VERA_ADDR_H = vbank | %00110000 ; 4-byte increment
cx16.VERA_ADDR_M = msb(vaddr)
cx16.VERA_ADDR_L = lsb(vaddr)
cx16.VERA_CTRL = 6<<1 ; dcsel = 6, fill the 32 bits cache
cx16.VERA_FX_CACHE_L = data
cx16.VERA_FX_CACHE_M = data
cx16.VERA_FX_CACHE_H = data
cx16.VERA_FX_CACHE_U = data
cx16.VERA_CTRL = 2<<1 ; dcsel = 2
cx16.VERA_FX_MULT = 0
cx16.VERA_FX_CTRL = %01000000 ; cache write enable
if (num_longwords & %1111110000000011) == 0 {
repeat lsb(num_longwords >> 2)
unroll 4 cx16.VERA_DATA0=0 ; write 4*4 bytes at a time, unrolled
}
else if (num_longwords & %1111111000000001) == 0 {
repeat lsb(num_longwords >> 1)
unroll 2 cx16.VERA_DATA0=0 ; write 2*4 bytes at a time, unrolled
}
else if (lsb(num_longwords) & 3) == 0 {
repeat num_longwords >> 2
unroll 4 cx16.VERA_DATA0=0 ; write 4*4 bytes at a time, unrolled
}
else if (lsb(num_longwords) & 1) == 0 {
repeat num_longwords >> 1
unroll 2 cx16.VERA_DATA0=0 ; write 2*4 bytes at a time, unrolled
}
else {
repeat num_longwords
cx16.VERA_DATA0=0 ; write 4 bytes at a time
}
cx16.VERA_FX_CTRL = 0 ; cache write disable
cx16.VERA_CTRL = 0
}
sub copy(ubyte srcbank, uword srcaddr, ubyte tgtbank, uword tgtaddr, uword num_longwords) {
; use cached 4-byte writes to quickly copy a portion of the video memory to somewhere else
; this routine is about 50% faster as a plain byte-by-byte copy
cx16.VERA_CTRL = 1
cx16.VERA_ADDR_H = srcbank | %00010000 ; source: 1-byte increment
cx16.VERA_ADDR_M = msb(srcaddr)
cx16.VERA_ADDR_L = lsb(srcaddr)
cx16.VERA_CTRL = 0
cx16.VERA_ADDR_H = tgtbank | %00110000 ; target: 4-byte increment
cx16.VERA_ADDR_M = msb(tgtaddr)
cx16.VERA_ADDR_L = lsb(tgtaddr)
cx16.VERA_CTRL = 2<<1 ; dcsel = 2
cx16.VERA_FX_MULT = 0
cx16.VERA_FX_CTRL = %01100000 ; cache write enable + cache fill enable
cx16.r0 = num_longwords
if (cx16.r0L & 1) == 0 {
repeat cx16.r0>>1 {
%asm {{
lda cx16.VERA_DATA1 ; fill cache with 4 source bytes...
lda cx16.VERA_DATA1
lda cx16.VERA_DATA1
lda cx16.VERA_DATA1
stz cx16.VERA_DATA0 ; write 4 bytes at once.
lda cx16.VERA_DATA1 ; fill cache with 4 source bytes...
lda cx16.VERA_DATA1
lda cx16.VERA_DATA1
lda cx16.VERA_DATA1
stz cx16.VERA_DATA0 ; write 4 bytes at once.
}}
}
} else {
repeat cx16.r0 {
%asm {{
lda cx16.VERA_DATA1 ; fill cache with 4 source bytes...
lda cx16.VERA_DATA1
lda cx16.VERA_DATA1
lda cx16.VERA_DATA1
stz cx16.VERA_DATA0 ; write 4 bytes at once.
}}
}
}
cx16.VERA_FX_CTRL = 0 ; cache write disable
cx16.VERA_CTRL = 0
}
asmsub mult16(uword value1 @R0, uword value2 @R1) clobbers(X) -> uword @AY {
; Returns the 16 bits unsigned result of R0*R1 in AY.
; Note: only the lower 16 bits! (the upper 16 bits are not valid for unsigned word multiplications, only for signed)
; Verafx doesn't support unsigned values like this for full 32 bit result.
%asm {{
lda cx16.r0
sta P8ZP_SCRATCH_W1
lda cx16.r0+1
sta P8ZP_SCRATCH_W1+1
jsr verafx.muls
ldx P8ZP_SCRATCH_W1
stx cx16.r0
ldx P8ZP_SCRATCH_W1+1
stx cx16.r0+1
rts
}}
}
asmsub muls(word value1 @R0, word value2 @R1) clobbers(X) -> word @AY, word @R0 {
; Returns the 32 bits signed result in AY and R0 (lower word, upper word).
; Vera Fx multiplication support only works on signed values!
%asm {{
lda #(2 << 1)
sta cx16.VERA_CTRL ; $9F25
stz cx16.VERA_FX_CTRL ; $9F29 (mainly to reset Addr1 Mode to 0)
lda #%00010000
sta cx16.VERA_FX_MULT ; $9F2C
lda #(6 << 1)
sta cx16.VERA_CTRL ; $9F25
lda cx16.r0
sta cx16.VERA_FX_CACHE_L ; $9F29
lda cx16.r0+1
sta cx16.VERA_FX_CACHE_M ; $9F2A
lda cx16.r1
sta cx16.VERA_FX_CACHE_H ; $9F2B
lda cx16.r1+1
sta cx16.VERA_FX_CACHE_U ; $9F2C
lda cx16.VERA_FX_ACCUM_RESET ; $9F29 (DCSEL=6)
; Set the ADDR0 pointer to $1f9bc and write our multiplication result there
; (these are the 4 bytes just before the PSG registers start)
lda #(2 << 1)
sta cx16.VERA_CTRL
lda #%01000000 ; Cache Write Enable
sta cx16.VERA_FX_CTRL
lda #$bc
sta cx16.VERA_ADDR_L
lda #$f9
sta cx16.VERA_ADDR_M
lda #$01
sta cx16.VERA_ADDR_H ; no increment
stz cx16.VERA_DATA0 ; multiply and write out result
lda #%00010001 ; $01 with Increment 1
sta cx16.VERA_ADDR_H ; so we can read out the result
lda cx16.VERA_DATA0 ; store the lower 16 bits of the result in AY
ldy cx16.VERA_DATA0
ldx cx16.VERA_DATA0 ; store the upper 16 bits of the result in R0
stx cx16.r0s
ldx cx16.VERA_DATA0
stx cx16.r0s+1
stz cx16.VERA_FX_CTRL ; Cache write disable
stz cx16.VERA_FX_MULT ; $9F2C reset multiply bit
stz cx16.VERA_CTRL ; reset DCSEL
rts
}}
}
sub transparency(bool enable) {
; Set transparent write mode for VeraFX cached writes and also for normal writes to DATA0/DATA.
; If enabled, pixels with value 0 do not modify VRAM when written (so they are "transparent")
cx16.VERA_CTRL = 2<<1 ; dcsel = 2
if enable
cx16.VERA_FX_CTRL |= %10000000
else
cx16.VERA_FX_CTRL &= %01111111
cx16.VERA_CTRL = 0
}
}