dragon-nx-32: commit initial bits of video development work

Not yet tested

diff --git a/Kernel/platform-dragon-nx32/kernel.def b/Kernel/platform-dragon-nx32/kernel.def
index daed265..f5b907a 100644 (file)
--- a/Kernel/platform-dragon-nx32/kernel.def
+++ b/Kernel/platform-dragon-nx32/kernel.def
@@ -5,6 +5,8 @@ U_DATA__TOTALSIZE           equ 0x300        ; 256+256+256 bytes.
 
 U_DATA_STASH                equ 0xFC00       ; FC00-FEFF
 
+VIDEO_BASE                 equ 0x0400       ; 6K for the display
+VIDEO_END                  equ 0x1C00
 
 ; Have these defined so that lowlevel-6809.s can be used as-is
 SAM_USER macro

diff --git a/Kernel/platform-dragon-nx32/video.s b/Kernel/platform-dragon-nx32/video.s
new file mode 100644 (file)
index 0000000..71f2048
--- /dev/null
+++ b/Kernel/platform-dragon-nx32/video.s
@@ -0,0 +1,255 @@
+       .module dragonvideo
+
+       ; Methods provided
+       .globl _vid256x192
+       .globl _plot_char
+       .globl _scroll_up
+       .globl _scroll_down
+       .globl _clear_across
+       .globl _clear_lines
+       .globl _cursor_on
+       .globl _cursor_off
+       ;
+       ; Imports
+       ;
+       .globl _fontdata_8x8
+
+       include "kernel.def"
+       include "../kernel09.def"
+
+       .area .text
+
+;
+;      Dragon video drivers
+;
+_vid256x192:
+       sta $ffc0
+       sta $ffc3
+       sta $ffc5
+       lda $ff22
+       anda #$07
+       ora #$f8
+       sta $ff22
+       rts
+
+;
+;      Compute the video base address
+;      A = X, B = Y
+;
+vidaddr:
+       ldy #VIDEO_BASE ; X is now the right column top line
+       leay a,y
+       clra
+       rorb    ; 3 right is as good as 5 left  
+       rora
+       rorb
+       rora
+       rorb
+       rora    ; D is now 32 * b
+       leay d,y
+       rts
+;
+;      plot_char(int8_t y, int8_t x, uint16_t c)
+;
+_plot_char:
+       pshs y
+       lda 4,s
+       bsr vidaddr             ; preserves X (holding the char)
+       tfr x,d
+       rolb                    ; multiply by 8
+       rola
+       rolb
+       rola
+       rolb
+       rola
+       tfr d,x
+       leax _fontdata_8x8,x            ; relative to font
+       lda ,x+                 ; simple 8x8 renderer for now
+       sta 0,y
+       lda ,x+
+       sta 32,y
+       lda ,x+
+       sta 64,y
+       lda ,x+
+       sta 96,y
+       lda ,x+
+       sta 128,y
+       lda ,x+
+       sta 160,y
+       lda ,x+
+       sta 192,y
+       lda ,x+
+       sta 224,y
+       puls y,pc
+
+;
+;      void scroll_up(void)
+;
+_scroll_up
+       pshs y
+       ldy VIDEO_BASE
+       leax 256,y
+vscrolln:
+       ; Unrolled line by line copy
+       ldd ,x++
+       std ,y++
+       ldd ,x++
+       std ,y++
+       ldd ,x++
+       std ,y++
+       ldd ,x++
+       std ,y++
+       ldd ,x++
+       std ,y++
+       ldd ,x++
+       std ,y++
+       ldd ,x++
+       std ,y++
+       ldd ,x++
+       std ,y++
+       ldd ,x++
+       std ,y++
+       ldd ,x++
+       std ,y++
+       ldd ,x++
+       std ,y++
+       ldd ,x++
+       std ,y++
+       ldd ,x++
+       std ,y++
+       ldd ,x++
+       std ,y++
+       ldd ,x++
+       std ,y++
+       ldd ,x++
+       std ,y++
+       cmpy video_endptr
+       bne vscrolln
+       puls y,pc
+
+;
+;      void scroll_down(void)
+;
+_scroll_down:
+       pshs y
+       ldy VIDEO_END
+       leax -256,y
+vscrolld:
+       ; Unrolled line by line loop
+       ldd ,--x
+       std ,--y
+       ldd ,--x
+       std ,--y
+       ldd ,--x
+       std ,--y
+       ldd ,--x
+       std ,--y
+       ldd ,--x
+       std ,--y
+       ldd ,--x
+       std ,--y
+       ldd ,--x
+       std ,--y
+       ldd ,--x
+       std ,--y
+       ldd ,--x
+       std ,--y
+       ldd ,--x
+       std ,--y
+       ldd ,--x
+       std ,--y
+       ldd ,--x
+       std ,--y
+       ldd ,--x
+       std ,--y
+       ldd ,--x
+       std ,--y
+       ldd ,--x
+       std ,--y
+       ldd ,--x
+       std ,--y
+       cmpx video_startptr
+       bne vscrolld
+       puls y,pc
+
+video_startptr:
+       .dw     VIDEO_BASE
+video_endptr:
+       .dw     VIDEO_END
+
+;
+;      clear_across(int8_t y, int8_t x, uint16_t l)
+;
+_clear_across:
+       pshs y
+       lda 4,s         ; x into A, B already has y
+       jsr vidaddr     ; Y now holds the address
+       tfr x,d         ; Shuffle so we are writng to X and the counter
+       tfr y,x         ; l is in d
+clearnext:
+       clr ,x
+       clr 32,x
+       clr 64,x
+       clr 96,x
+       clr 128,x
+       clr 160,x
+       clr 192,x
+       clr 224,x
+       leax 1,x
+       deca
+       bne clearnext
+       puls y,pc
+;
+;      clear_lines(int8_t y, int8_t ct)
+;
+_clear_lines:
+       pshs y
+       clra                    ; b holds Y pos already
+       jsr vidaddr             ; y now holds ptr to line start
+       tfr y,x
+       clra
+       clrb
+wipel:
+       std ,x++
+       std ,x++
+       std ,x++
+       std ,x++
+       std ,x++
+       std ,x++
+       std ,x++
+       std ,x++
+       std ,x++
+       std ,x++
+       std ,x++
+       std ,x++
+       std ,x++
+       std ,x++
+       std ,x++
+       std ,x++
+       dec 4,s                 ; count of lines
+       bne wipel
+       puls y,pc
+
+_cursor_on
+       pshs y
+       lda  4,s
+       jsr vidaddr
+       tfr y,x
+       puls y
+       stx cursor_save
+       ; Fall through
+_cursor_off
+       ldx cursor_save
+       com ,x
+       com 32,x
+       com 64,x
+       com 96,x
+       com 128,x
+       com 160,x
+       com 192,x
+       com 224,x
+       rts
+
+       .area .data
+cursor_save:
+       .dw     0