From: Alan Cox <alan@etchedpixels.co.uk>
Date: Sun, 25 Oct 2015 14:13:15 +0000 (+0000)
Subject: trs80: test implementation of "exchange" operator
X-Git-Url: https://git.ndcode.org/public/gitweb.cgi?a=commitdiff_plain;h=a20c0de92483882844a32bc9af596820308286f1;p=FUZIX.git

trs80: test implementation of "exchange" operator

On the TRS80 at least it should be much faster than read/write
---

diff --git a/Kernel/platform-trs80/devgfx.c b/Kernel/platform-trs80/devgfx.c
index 82ce21c0..d803d8ef 100644
--- a/Kernel/platform-trs80/devgfx.c
+++ b/Kernel/platform-trs80/devgfx.c
@@ -73,6 +73,7 @@ static int gfx_draw_op(uarg_t arg, char *ptr, uint8_t *buf)
     break;
   case GFXIOC_WRITE:
   case GFXIOC_READ:
+  case GFXIOC_EXG:
     if (l < 8)
       return EINVAL;
     l -= 8;
@@ -80,13 +81,17 @@ static int gfx_draw_op(uarg_t arg, char *ptr, uint8_t *buf)
       p[0] + p[2] > 128 || p[1] + p[3] > 255 ||
       (p[2] * p[3]) > l)
       return -EFAULT;
-    if (arg == GFXIOC_READ) {
-      video_read(buf);
-      if (uput(buf + 8, ptr, l))
+    if (arg == GFXIOC_WRITE)
+      video_write(buf);
+    else {
+      if (arg == GFXIOC_READ)
+        video_read(buf);
+      else
+        video_exg(buf);
+      if (uput(buf + 10, ptr, l - 2))
         return EFAULT;
       return 0;
     }
-    video_write(buf);
   }
   return 0;
 }
@@ -123,6 +128,7 @@ int gfx_ioctl(uint8_t minor, uarg_t arg, char *ptr)
   case GFXIOC_DRAW:
   case GFXIOC_READ:
   case GFXIOC_WRITE:
+  case GFXIOC_EXG:
     if (vmode == 1) {
       uint8_t *tmp = (uint8_t *)tmpbuf();
       err = gfx_draw_op(arg, ptr, tmp);
diff --git a/Kernel/platform-trs80/devgfx.h b/Kernel/platform-trs80/devgfx.h
index d58afe7e..c29616d8 100644
--- a/Kernel/platform-trs80/devgfx.h
+++ b/Kernel/platform-trs80/devgfx.h
@@ -7,5 +7,6 @@ extern int gfx_ioctl(uint8_t minor, uarg_t arg, char *ptr);
 extern void video_cmd(uint8_t *ptr);
 extern void video_read(uint8_t *ptr);
 extern void video_write(uint8_t *ptr);
+extern void video_exg(uint8_t *ptr);
 
 #endif
diff --git a/Kernel/platform-trs80/trs80.s b/Kernel/platform-trs80/trs80.s
index 52a9a8fa..40f71788 100644
--- a/Kernel/platform-trs80/trs80.s
+++ b/Kernel/platform-trs80/trs80.s
@@ -21,6 +21,7 @@
 	    .globl _video_cmd
 	    .globl _video_read
 	    .globl _video_write
+	    .globl _video_exg
 
             ; exported debugging tools
             .globl _trap_monitor
@@ -267,3 +268,38 @@ _video_read:
 	    ld (patch_io + 1), a
 	    ld a, #0x13			; autoincrement on read
 	    jr video_do
+
+_video_exg:				; not quite worth self modifying
+	    ld a, #0xB3			; this one too
+	    ld (patch_io + 1), a	; OTIR
+	    ld a, #0x43
+	    out (0x83), a		; autoincrement on write
+	    pop de
+	    pop iy
+	    push iy
+	    push de
+	    push iy
+	    pop hl
+	    ld de, #8
+	    add hl, de			; Data start into HL
+	    ld e, (iy)			; x
+	    ld d, 2(iy)			; y
+next_ex:
+	    ld c, #0x80
+	    out (c), e			; x
+	    inc c
+	    out (c), d			; y
+	    ld b, 4(iy)			; count of bytes per line
+ex_line:
+	    in a, (0x82)		; faster than in a,(c)
+	    ex af,af'			; icky but no free registers
+	    ld a, (hl)
+	    out (0x82), a		; write and inc
+	    ex af, af
+	    ld (hl), a
+	    inc hl
+	    djnz ex_line
+	    inc d			; next line
+	    dec 6(iy)			; height
+	    jr nz, next_ex
+	    ret