Working on mega65 DMA line drawer. Works for fixed x1, y1.

src/main/fragment/mos6502-common/vdsm1=vdsc1_plus_vwsm2.asm

@@ -0,0 +1,19 @@
+lda {m2}+1
+ora #$7f
+bmi !+
+lda #0
+!:
+sta $ff
+lda {m2}
+clc
+adc #<{c1}
+sta {m1}
+lda {m2}+1
+adc #>{c1}
+sta {m1}+1
+lda $ff
+adc #<{c1}>>$10
+sta {m1}+2
+lda $ff
+adc #>{c1}>>$10
+sta {m1}+3

src/main/fragment/mos6502-common/vdsm1=vdsm1_plus_vwsm2.asm

@@ -17,4 +17,3 @@ sta {m1}+2
 lda {m1}+3
 adc $ff
 sta {m1}+3
-

src/main/fragment/mos6502-common/vdsm1=vdsm2_plus_vbsaa.asm

@@ -0,0 +1,19 @@
+pha
+ora #$7f
+bmi !+
+lda #0
+!:
+sta $ff
+clc
+pla
+adc {m2}
+sta {m1}
+lda {m2}+1
+adc $ff
+sta {m1}+1
+lda {m2}+2
+adc $ff
+sta {m1}+2
+lda {m2}+3
+adc $ff
+sta {m1}+3

src/main/fragment/mos6502-common/vdsm1=vdsm2_plus_vdsm3.asm

@@ -0,0 +1,13 @@
+clc
+lda {m2}
+adc {m3}
+sta {m1}
+lda {m2}+1
+adc {m3}+1
+sta {m1}+1
+lda {m2}+2
+adc {m3}+2
+sta {m1}+2
+lda {m2}+3
+adc {m3}+3
+sta {m1}+3

src/main/fragment/mos6502-common/vdsm1=vwsm2_plus_vwsm3.asm

@@ -0,0 +1,25 @@
+lda {m3}+1
+ora #$7f
+bmi !+
+lda #0
+!:
+sta $ff
+lda {m2}+1
+ora #$7f
+bmi !+
+lda #0
+!:
+sta $fe
+clc
+lda {m2}
+adc {m3}
+sta {m1}
+lda {m2}+1
+adc {m3}+1
+sta {m1}+1
+lda $fe
+adc $ff
+sta {m1}+2
+lda $fe
+adc $ff
+sta {m1}+3

src/main/fragment/mos6502-common/vwsm1=vwsm1_rol_8.asm

@@ -0,0 +1,4 @@
+lda {m1}
+sta {m1}+1
+lda #0
+sta {m1}

src/main/fragment/mos6502-common/vwsm1=vwsm1_ror_8.asm

@@ -0,0 +1,7 @@
+lda {m1}+1
+sta {m1}
+ora #$7f
+bmi !+
+lda #0
+!:
+sta {m1}+1

src/main/fragment/mos6502-common/vwsm1=vwsm2_ror_8.asm

@@ -1,7 +1,7 @@
 lda {m2}+1
 sta {m1}
-and #$80
-beq !+
-lda #$ff
+ora #$7f
+bmi !+
+lda #0
 !:
 sta {m1}+1

src/main/fragment/mos6502-common/vwum1=_lo_vdsm2.asm

@@ -0,0 +1,4 @@
+lda {m2}
+sta {m1}
+lda {m2}+1
+sta {m1}+1

src/main/kc/lib/mega65-memorymapper.c

@@ -106,7 +106,7 @@ void memoryRemap256M(unsigned char remapBlocks, unsigned long lowerPageOffset, u
         lda lMb     // lower blocks offset megabytes
         ldx #$0f    // lower signal for MB offset
         ldy uMb     // upper blocks offset megabytes
-        ldz #$00    // upper signal for MB offset
+        ldz #$0f    // upper signal for MB offset
         map
         lda aVal    // lower blocks offset page low
         ldx xVal    // lower blocks to map + lower blocks offset high nibble

src/test/kc/examples/mega65/linedrawing.c

@@ -1,11 +1,13 @@
 // Test hardware line drawing
 // Based on https://github.com/MEGA65/mega65-tools/blob/master/src/tests/test_290.c
 
-#pragma target(mega65)
+#pragma target(mega65_remote)
 #include <mega65.h>
+#include <mega65-dma.h>
 #include <6502.h>
 
 #define POKE(addr,val) *((char*)(addr)) = val
+#define PEEK(addr) *((char*)addr)
 
 // Poke a value directly into memory
 // - addr: The 32bit address to poke to
@@ -19,23 +21,60 @@ void lpoke(__zp unsigned long addr, char val) {
     }
 }
 
+char line_dmalist[256];
+char slope_ofs, line_mode_ofs, cmd_ofs, count_ofs;
+char src_ofs, dst_ofs;
+
 void main() {
 
-    // Avoid interrupts
-    SEI();
-    // Map memory to BANK 0 : 0x00XXXX - giving access to I/O
-    memoryRemap(0,0,0);
+  // Avoid interrupts
+  SEI();
 
-    // Fast CPU, M65 IO
-    POKE(0, 65);
-    POKE(0xD02F, 0x47);
-    POKE(0xD02F, 0x53);    
+  // Map memory to BANK 0 : 0x00XXXX - giving access to I/O
+  memoryRemap(0x00,0,0);
+  // Fast CPU, M65 IO
+  POKE(0, 65);
+  POKE(0xD02F, 0x47);
+  POKE(0xD02F, 0x53);    
+  // No C65 ROMs are mapped
+  POKE(0xD030, 0x00);    
 
-    graphics_mode();
+  graphics_mode();
 
-    for(;;) ;
 
 
+   // Set up common structure of the DMA list
+   char ofs = 0;
+  // Screen layout is in vertical stripes, so we need only to setup the
+  // X offset step.  64x25 =
+  line_dmalist[ofs++] = 0x87;
+  line_dmalist[ofs++] = (1600 - 8) & 0xff;
+  line_dmalist[ofs++] = 0x88;
+  line_dmalist[ofs++] = (1600 - 8) >> 8;
+  line_dmalist[ofs++] = 0x8b;
+  slope_ofs = ofs++; // remember where we have to put the slope in
+  line_dmalist[ofs++] = 0x8c;
+  ofs++;
+  line_dmalist[ofs++] = 0x8f;
+  line_mode_ofs = ofs++;
+  line_dmalist[ofs++] = 0x0a; // F018A list format
+  line_dmalist[ofs++] = 0x00; // end of options
+  cmd_ofs = ofs++;            // command byte
+  count_ofs = ofs;
+  ofs += 2;
+  src_ofs = ofs;
+  ofs += 3;
+  dst_ofs = ofs;
+  ofs += 3;
+  line_dmalist[ofs++] = 0x00; // modulo
+  line_dmalist[ofs++] = 0x00;
+
+
+  int x1 = 160;
+  for(int x2=0;x2<320;x2+=11) {
+    draw_line(x1, 100, x2, 198, 1);  
+  }
+
 }
 
 
@@ -76,5 +115,164 @@ void graphics_mode(void) {
   POKE(0xD020, 0);
   POKE(0xD021, 0);
 
+  // Fill the graphics
+  memset_dma256(0x0, 0x4, 0x0000, 0x00, 320*200);
+  memset_dma256(0x0, 0x4, 0x0000, 0x055, 8*200);
+  memset_dma256(0x0, 0x4, 0x0000+200*39*8, 0x055, 8*200);
+
+
 }
 
+
+void draw_line(int x1, int y1, int x2, int y2, unsigned char colour)
+{
+  long addr;
+  int temp, slope, dx, dy;
+
+  // Ignore if we choose to draw a point
+  if (x2 == x1 && y2 == y1)
+    return;
+
+  dx = x2 - x1;
+  dy = y2 - y1;
+  if (dx < 0)
+    dx = -dx;
+  if (dy < 0)
+    dy = -dy;
+
+  //  snprintf(msg,41,"(%d,%d) - (%d,%d)    ",x1,y1,x2,y2);
+  //  print_text(0,1,1,msg);
+
+  // Draw line from x1,y1 to x2,y2
+  if (dx < dy) {
+    // Y is major axis
+
+    if (y2 < y1) {
+      temp = x1;
+      x1 = x2;
+      x2 = temp;
+      temp = y1;
+      y1 = y2;
+      y2 = temp;
+    }
+
+    // Use hardware divider to get the slope
+    POKE(0xD770, (char)(dx & 0xff));
+    POKE(0xD771, (char)(dx >> 8));
+    POKE(0xD772, 0);
+    POKE(0xD773, 0);
+    POKE(0xD774, (char)(dy & 0xff));
+    POKE(0xD775, (char)(dy >> 8));
+    POKE(0xD776, 0);
+    POKE(0xD777, 0);
+
+    // Wait 16 cycles
+    POKE(0xD020, 0);
+    POKE(0xD020, 0);
+    POKE(0xD020, 0);
+    POKE(0xD020, 0);
+
+    // Slope is the most significant bytes of the fractional part
+    // of the division result
+    slope = (int)PEEK(0xD76A) + ((int)PEEK(0xD76B) << 8);
+
+    // Put slope into DMA options
+    line_dmalist[slope_ofs] = (char)(slope & 0xff);
+    line_dmalist[slope_ofs + 2] = (char)(slope >> 8);
+
+    // Load DMA dest address with the address of the first pixel
+    addr = 0x40000 + (y1 << 3) + (x1 & 7) + (x1 >> 3) * 64 * 25l;
+    line_dmalist[dst_ofs + 0] = <(<(addr));
+    line_dmalist[dst_ofs + 1] = >(<(addr));
+    line_dmalist[dst_ofs + 2] = <(>(addr));
+
+    // Source is the colour
+    line_dmalist[src_ofs] = colour & 0xf;
+
+    // Count is number of pixels, i.e., dy.
+    line_dmalist[count_ofs] = (char)(dy & 0xff);
+    line_dmalist[count_ofs + 1] = (char)(dy >> 8);
+
+    // Command is FILL
+    line_dmalist[cmd_ofs] = 0x03;
+
+    // Line mode active, major axis is Y
+    line_dmalist[line_mode_ofs] = 0x80 + 0x40 + (((x2 - x1) < 0) ? 0x20 : 0x00);
+
+    //    snprintf(msg,41,"Y: (%d,%d) - (%d,%d) m=%04x",x1,y1,x2,y2,slope);
+    //    print_text(0,2,1,msg);
+
+    POKE(0xD020, 1);
+
+    POKE(0xD701, (char)(((unsigned int)(line_dmalist)) >> 8));
+    POKE(0xD705, (char)(((unsigned int)(line_dmalist)) >> 0));
+
+    POKE(0xD020, 0);
+  }
+  else {
+    // X is major axis
+
+    if (x2 < x1) {
+      temp = x1;
+      x1 = x2;
+      x2 = temp;
+      temp = y1;
+      y1 = y2;
+      y2 = temp;
+    }
+
+    // Use hardware divider to get the slope
+    POKE(0xD770, (char)(dy & 0xff));
+    POKE(0xD771, (char)(dy >> 8));
+    POKE(0xD772, 0);
+    POKE(0xD773, 0);
+    POKE(0xD774, (char)(dx & 0xff));
+    POKE(0xD775, (char)(dx >> 8));
+    POKE(0xD776, 0);
+    POKE(0xD777, 0);
+
+    // Wait 16 cycles
+    POKE(0xD020, 0);
+    POKE(0xD020, 0);
+    POKE(0xD020, 0);
+    POKE(0xD020, 0);
+
+    // Slope is the most significant bytes of the fractional part
+    // of the division result
+    slope = (int)PEEK(0xD76A) + ((int)PEEK(0xD76B) << 8);
+
+    // Put slope into DMA options
+    line_dmalist[slope_ofs] = (char)(slope & 0xff);
+    line_dmalist[slope_ofs + 2] = (char)(slope >> 8);
+
+    // Load DMA dest address with the address of the first pixel
+    addr = 0x40000 + (y1 << 3) + (x1 & 7) + (x1 >> 3) * 64 * 25;
+    line_dmalist[dst_ofs + 0] = <(<(addr));
+    line_dmalist[dst_ofs + 1] = >(<(addr));
+    line_dmalist[dst_ofs + 2] = <(>(addr));
+
+    // Source is the colour
+    line_dmalist[src_ofs] = colour & 0xf;
+
+    // Count is number of pixels, i.e., dy.
+    line_dmalist[count_ofs] = (char)(dx & 0xff);
+    line_dmalist[count_ofs + 1] = (char)(dx >> 8);
+
+    // Command is FILL
+    line_dmalist[cmd_ofs] = 0x03;
+
+    // Line mode active, major axis is X
+    char line_mode = (((y2 - y1) < 0) ? 0x20 : 0x00);
+    line_dmalist[line_mode_ofs] = 0x80 + 0x00 + line_mode;
+
+    //    snprintf(msg,41,"X: (%d,%d) - (%d,%d) m=%04x",x1,y1,x2,y2,slope);
+    //    print_text(0,2,1,msg);
+
+    POKE(0xD020, 1);
+
+    POKE(0xD701, (char)(((unsigned int)(line_dmalist)) >> 8));
+    POKE(0xD705, (char)(((unsigned int)(line_dmalist)) >> 0));
+
+    POKE(0xD020, 0);
+  }
+}