2 ; Ullrich von Bassewitz, 21.06.2002
4 ; Common functions of the tgi graphics kernel.
7 .include "tgi-kernel.inc"
8 .include "tgi-error.inc"
11 .interruptor tgi_irq ; Export as IRQ handler
14 ;----------------------------------------------------------------------------
19 _tgi_drv: .res 2 ; Pointer to driver
20 _tgi_error: .res 1 ; Last error code
21 _tgi_gmode: .res 1 ; Flag: Graphics mode active
22 _tgi_curx: .res 2 ; Current drawing cursor X
23 _tgi_cury: .res 2 ; Current drawing cursor Y
24 _tgi_color: .res 1 ; Current drawing color
25 _tgi_textdir: .res 1 ; Current text direction
26 ; The following two store an 8.8 fixed point value in the first two bytes,
27 ; and a rounded integer value in the third byte. The latter is passed to the
28 ; driver to scale the bitmap font. The variables are expected to be in
29 ; this order and adjacent.
30 _tgi_textmagw: .res 3 ; Text magnification for the width
31 _tgi_textmagh: .res 3 ; Text magnification for the height
33 ; The following two must also be in exactly this order
34 _tgi_charwidth: .res 1 ; Char width of system font
35 _tgi_charheight: .res 1 ; Char height of system font
37 ; The following variables are copied from the driver header for faster access
38 ; fontwidth and fontheight are expected to be in order and adjacent.
40 _tgi_xres: .res 2 ; X resolution of the current mode
41 _tgi_yres: .res 2 ; Y resolution of the current mode
42 _tgi_colorcount: .res 1 ; Number of available colors
43 _tgi_pagecount: .res 1 ; Number of available screen pages
44 _tgi_fontwidth: .res 1 ; System font width in pixels
45 _tgi_fontheight: .res 1 ; System font height in pixels
46 _tgi_aspectratio: .res 2 ; Aspect ratio in 8.8 fixed point
51 ; Jump table for the driver functions.
53 tgi_install: jmp $0000
54 tgi_uninstall: jmp $0000
57 tgi_geterror: jmp $0000
58 tgi_control: jmp $0000
60 tgi_setviewpage: jmp $0000
61 tgi_setdrawpage: jmp $0000
62 tgi_setcolor: jmp $0000
63 tgi_setpalette: jmp $0000
64 tgi_getpalette: jmp $0000
65 tgi_getdefpalette: jmp $0000
66 tgi_setpixel: jmp $0000
67 tgi_getpixel: jmp $0000
70 tgi_textstyle: jmp $0000
71 tgi_outtext: jmp $0000
72 tgi_irq: .byte $60, $00, $00 ; RTS plus two dummy bytes
74 ; Driver header signature
76 tgi_sig: .byte $74, $67, $69, TGI_API_VERSION ; "tgi", version
80 ;----------------------------------------------------------------------------
81 ; void __fastcall__ tgi_install (void* driver);
82 ; /* Install an already loaded driver. */
91 ; Check the driver signature
93 ldy #.sizeof(tgi_sig)-1
100 ; Copy the jump vectors
102 ldy #TGI_HDR::JUMPTAB
104 @L1: inx ; Skip JMP opcode
105 jsr copy ; Copy one byte
106 jsr copy ; Copy one byte
107 cpy #(TGI_HDR::JUMPTAB + .sizeof(TGI_HDR::JUMPTAB))
110 ; Call the driver install routine. It may update header variables, so we copy
111 ; them after this call.
115 ; Copy variables from the driver header for faster access.
117 jsr tgi_set_ptr ; Set ptr1 to tgi_drv
118 ldy #(TGI_HDR::VARS + .sizeof(TGI_HDR::VARS) - 1)
119 ldx #.sizeof(TGI_HDR::VARS)-1
121 sta tgi_driver_vars,x
126 ; Install the IRQ vector if the driver needs it.
128 lda tgi_irq+2 ; Check high byte of IRQ vector
129 beq @L4 ; Jump if vector invalid
130 lda #$4C ; Jump opcode
131 sta tgi_irq ; Activate IRQ routine
133 ; Initialize some other variables
137 @L5: sta _tgi_error,x ; Clear error/mode/curx/cury/textdir
143 ; Copy one byte from the jump vectors
151 ;----------------------------------------------------------------------------
152 ; Set an invalid argument error
159 ;----------------------------------------------------------------------------
160 ; Set an invalid driver error
163 lda #TGI_ERR_INV_DRIVER
167 ;----------------------------------------------------------------------------
168 ; Load the pointer to the tgi driver into ptr1.
177 ;----------------------------------------------------------------------------
178 ; void __fastcall__ tgi_uninstall (void);
179 ; /* Uninstall the currently loaded driver but do not unload it. Will call
180 ; * tgi_done if necessary.
184 jsr _tgi_done ; Switch off graphics
186 jsr tgi_uninstall ; Allow the driver to clean up
188 lda #$60 ; RTS opcode
189 sta tgi_irq ; Disable IRQ entry point
191 ; Clear driver pointer and error code