dragon-nx32: graphics: fold in read/write together.

diff --git a/Kernel/platform-dragon-nx32/video.s b/Kernel/platform-dragon-nx32/video.s
index 060b0a4..673c45b 100644 (file)
--- a/Kernel/platform-dragon-nx32/video.s
+++ b/Kernel/platform-dragon-nx32/video.s
@@ -339,23 +339,43 @@ nocursor:
 ;      because everything in the X plane is bytewide.
 ;
 _video_write:
-       pshs u
-       bsr vidptr
-       tfr x,y                 ; So we can use y to get at the w/h
-       leax 4,x                ; Move on to data space
-vwnext:
-       lda 3,y
-       pshs u
-vwline:
-       ldb ,x+
-       stb ,u+
-       deca
-       bne vwline
-       puls u
-       leau 32,u
-       dec 1,y
-       bne vwnext
-       puls u,pc
+       clra                    ; clr C
+       bra     tfr_cmd
+_video_read:
+       coma                    ; set C
+       bra     tfr_cmd         ; go
+
+;;; This does the job of READ & WRITE
+;;;   takes: C = direction 0=write, 1=read
+;;;   takes: X = transfer buffer ptr + 2
+tfr_cmd:
+       pshs    u,y             ; save regs
+       orcc    #$10            ; turn off interrupt - int might remap kernel
+       ldd     #$80c0          ; this is writing
+       bcc     c@              ; if carry clear then keep D write
+       exg     a,b             ; else flip D: now is reading
+c@     sta     b@+1            ; !!! self modify inner loop
+       stb     b@+3            ; !!!  
+       bsr     vidptr          ; U = screen addr
+       tfr     x,y             ; Y = ptr to Height, width
+       leax    4,x             ; X = pixel data
+       ;; outter loop: iterate over pixel rows
+a@     lda     3,y             ; count = width
+       pshs    u               ; save screen ptr
+       ;; inner loop: iterate over columns
+       ;; modify mod+1 and mod+3 to switch directions
+b@     ldb     ,x+             ; get a byte from src
+       stb     ,u+             ; save byte to dest
+       deca                    ; bump counter
+       bne     b@              ; loop
+       ;; increment outer loop
+       puls    u               ; restore original screen ptr
+       leau    32,u            ; add byte span of screen (goto next line)
+       dec     1,y             ; bump row counter
+       bne     a@              ; loop
+       puls    u,y,pc          ; restore regs, return
+       
+
 ;
 ;      Find the address we need on a pixel row basis
 ;
@@ -368,27 +388,6 @@ vidptr:
        ldd ,x++                ; X
        leau d,u
        rts
-;
-;      FIXME - fold read/write into one self modifier
-;
-_video_read:
-       pshs u
-       bsr vidptr
-       tfr x,y                 ; So we can use y to get at the w/h
-       leax 4,x                ; Move on to data space
-vrnext:
-       lda 3,y                 ; a counts our copy along the scan line
-       pshs u
-vrline:
-       ldb ,u+                 ; b does our data
-       stb ,x+
-       deca
-       bne vrline
-       puls u                  ; step down a line
-       leau 32,u
-       dec 1,y                 ; use the buffer directly for line count
-       bne vrnext
-       puls u,pc               ; and done
 
 _video_cmd:
        pshs u