From 8b0c3d342513f6762b2c791a286f2ec2fab428fc Mon Sep 17 00:00:00 2001
From: cuz <cuz@b7a2c559-68d2-44c3-8de9-860c34a00d81>
Date: Sun, 7 Nov 2004 11:30:26 +0000
Subject: [PATCH] Use the new TGI_HDR structure. Added an interrupt entry point
 for the drivers. Rewrote tgi_unload to avoid problems with the tgi_drv
 pointer.

git-svn-id: svn://svn.cc65.org/cc65/trunk@3284 b7a2c559-68d2-44c3-8de9-860c34a00d81
---
 libsrc/tgi/tgi-kernel.s | 53 +++++++++++++++++++++++------------------
 libsrc/tgi/tgi_unload.s | 27 ++++++++++++++-------
 2 files changed, 49 insertions(+), 31 deletions(-)

diff --git a/libsrc/tgi/tgi-kernel.s b/libsrc/tgi/tgi-kernel.s
index a78a45581..4cf9f8519 100644
--- a/libsrc/tgi/tgi-kernel.s
+++ b/libsrc/tgi/tgi-kernel.s
@@ -7,8 +7,8 @@
         .include        "tgi-kernel.inc"
         .include        "tgi-error.inc"
 
-        .export         tgi_clear_ptr
         .importzp       ptr1
+        .interruptor    tgi_irq         ; Export as IRQ handler
 
 
 ;----------------------------------------------------------------------------
@@ -34,7 +34,6 @@ _tgi_colorcount:    .res    1           ; Number of available colors
 _tgi_pagecount:     .res    1           ; Number of available screen pages
 _tgi_fontsizex:     .res    1           ; System font X size
 _tgi_fontsizey:     .res    1           ; System font Y size
-tgi_driver_var_size     = * - tgi_driver_vars
 
 
 .data
@@ -61,11 +60,11 @@ tgi_bar:            jmp     $0000
 tgi_circle:         jmp     $0000
 tgi_textstyle:      jmp     $0000
 tgi_outtext:        jmp     $0000
+tgi_irq:            .byte   $60, $00, $00       ; RTS plus two dummy bytes
 
 ; Driver header signature
 .rodata
 tgi_sig:        .byte   $74, $67, $69, TGI_API_VERSION  ; "tgi", version
-tgi_sig_len     = * - tgi_sig
 
 
 ;----------------------------------------------------------------------------
@@ -81,7 +80,7 @@ _tgi_install:
 
 ; Check the driver signature
 
-        ldy     #tgi_sig_len-1
+        ldy     #.sizeof(tgi_sig)-1
 @L0:    lda     (ptr1),y
         cmp     tgi_sig,y
         bne     tgi_inv_drv
@@ -90,39 +89,44 @@ _tgi_install:
 
 ; Copy the jump vectors
 
-        ldy     #TGI_HDR_JUMPTAB
+        ldy     #TGI_HDR::JUMPTAB
         ldx     #0
 @L1:    inx                             ; Skip JMP opcode
         jsr     copy                    ; Copy one byte
         jsr     copy                    ; Copy one byte
-        cpx     #(TGI_HDR_JUMPCOUNT*3)
+        cpx     #(TGI_HDR::JUMPTAB + .sizeof(TGI_HDR::JUMPTAB))
         bne     @L1
 
-; Call the driver install routine
+; Call the driver install routine. It may update header variables, so we copy
+; them after this call.
 
-        jsr     tgi_install             ; Call driver install routine, may...
-                                        ; ...update variables
-        jsr     tgi_set_ptr             ; Set ptr1 to tgi_drv
+        jsr     tgi_install
 
-; Copy variables. Beware: We are using internal knowledge about variable
-; layout here!
+; Copy variables from the driver header for faster access.
 
-        ldy     #TGI_HDR_XRES
-        ldx     #0
+        jsr     tgi_set_ptr             ; Set ptr1 to tgi_drv
+        ldy     #(TGI_HDR::VARS + .sizeof(TGI_HDR::VARS) - 1)
+        ldx     #.sizeof(TGI_HDR::VARS)-1
 @L3:    lda     (ptr1),y
         sta     tgi_driver_vars,x
-        iny
-        inx
-        cpx     #tgi_driver_var_size
-        bne     @L3
+        dey
+        dex
+        bpl     @L3
+
+; Install the IRQ vector if the driver needs it.
+
+        lda     tgi_irq+2               ; Check high byte of IRQ vector
+        beq     @L4                     ; Jump if vector invalid
+   	lda	#$4C			; Jump opcode
+       	sta    	tgi_irq                 ; Activate IRQ routine
 
-; Initialize variables
+; Initialize some other variables
 
         lda     #$00
-        ldx     #7-1
-@L4:    sta     _tgi_error,x            ; Clear error/mode/curx/cury/textdir
+@L4:    ldx     #8-1
+@L5:    sta     _tgi_error,x            ; Clear error/mode/curx/cury/textdir
         dex
-        bpl     @L4
+        bpl     @L5
 
 	rts
 
@@ -168,11 +172,14 @@ tgi_set_ptr:
 
 _tgi_uninstall:
         jsr     _tgi_done               ; Switch off graphics
+
         jsr     tgi_uninstall           ; Allow the driver to clean up
 
+	lda	#$60                    ; RTS opcode
+	sta	tgi_irq                 ; Disable IRQ entry point
+
 ; Clear driver pointer and error code
 
-tgi_clear_ptr:                          ; External entry point
         lda     #$00
         sta     _tgi_drv
         sta     _tgi_drv+1
diff --git a/libsrc/tgi/tgi_unload.s b/libsrc/tgi/tgi_unload.s
index 69171de32..66a318fcd 100644
--- a/libsrc/tgi/tgi_unload.s
+++ b/libsrc/tgi/tgi_unload.s
@@ -6,20 +6,31 @@
 
 
         .include        "tgi-kernel.inc"
+        .include        "tgi-error.inc"
         .include        "modload.inc"
 
-        .import         tgi_clear_ptr
 
-.proc   _tgi_unload
+_tgi_unload:
 
-        jsr     _tgi_done               ; Switch off graphics
-        jsr     tgi_uninstall           ; Allow the driver to clean up
+        lda     _tgi_drv
+        ora     _tgi_drv
+        beq     no_driver               ; No driver
 
         lda     _tgi_drv
-        ldx     _tgi_drv+1
-        jsr     _mod_free               ; Free the driver
+        pha
+        lda     _tgi_drv+1
+        pha                             ; Save pointer to driver
+
+        jsr     _tgi_uninstall          ; Uninstall the driver
+
+        pla
+        tax
+        pla
+        jmp     _mod_free               ; Free the driver
 
-        jmp     tgi_clear_ptr           ; Clear the driver pointer and exit
+no_driver:
+        lda     #<TGI_ERR_NO_DRIVER
+        sta     _tgi_error
+        rts
 
-.endproc
 
-- 
2.39.5