Rewrite start condition of line_down so that it start on exaktly the right pixel

wip-hugo/macros/16aritmatic.s

@@ -80,6 +80,7 @@
 
 ;;Larger then operation, uses the A register
 ;;IF a < b then: jump to label
+; C =0 if jump to LABEL
 .macro Lag_16 a_low, a_hi, b_low, b_hi, label ; [low, hi] = [low, hi]*2
         LDA a_hi
         CMP b_hi

wip-hugo/routines/line/line_down.s

@@ -51,7 +51,7 @@
         Sub_16 >D, <D, dx, #$00
 
         jsr pixel_draw ;;only used first pixel. after this relative position is abused
-        LDY #$00
+        ;LDY #$00
         LDX X_pos
 for_x:
         ;; Paints A to address i btp_mem_pos* + Y
@@ -82,10 +82,9 @@ increment_y_pos:
         CPY #$08 ;
         BNE for_x
 move_8px_down: ; Z=1 --> C=1
-        ;; +320-8 bytes
         LDY #$00
-        Add_16 >btp_mem_pos, <btp_mem_pos, #$40, #$01
+        Add_16 >btp_mem_pos, <btp_mem_pos, #$40, #$01; +320
-        jmp for_x
+        JMP for_x
 increment_y_pos_end:
 case_2: ;; C =0 because LAG_16 so we can use !
         Add_16 >D, <D, >dy_2, <dy_2, ! ;D = D + 2*dy

wip-hugo/routines/line/line_down_inv.s

@@ -65,8 +65,8 @@ increment_y_pos_end:
         ;;If D <  %00000010 00000000:  case_2
         ;;else case 1.
         Lag_16 >D, <D, #$00, #$02, case_2
-case_1:
+case_1:; C = 1 because LAG
-        Sub_16 >D, <D, >V, <V; D = D - V
+        Sub_16 >D, <D, >V, <V, !; D = D - V
 increment_pixel_x:
         LDA byte_to_paint
         LSR byte_to_paint

wip-hugo/routines/line/line_test.s

@@ -6,9 +6,9 @@
         X_pos_ = $0E
         Y_end_ = $10
         X_end_ = $11
-        LDA #$d0
+        LDA #$d2
         STA X_pos_
-        LDA #$60
+        LDA #$62
         STA Y_pos_
         LDA #$ff
         STA X_end

wip-hugo/routines/memory/pixel_draw.s

@@ -47,14 +47,18 @@ end__:
 	LDA #%00000111 ; A = y (mod 8)
 	AND Y_pos ;; offset to add
 
+
 	;;ading offset, same as psudocode bellow
 	;;Add_16 >btp_mem_pos, <btp_mem_pos, A, #$00
-	CLC ; Y = b_low
+	;CLC ; Y = b_low
-	ADC >btp_mem_pos
+	;ADC >btp_mem_pos
-	STA >btp_mem_pos
+	;STA >btp_mem_pos
-	LDA #$00
+	;LDA #$00
-	ADC <btp_mem_pos ; C =0
+	;ADC <btp_mem_pos ; C =0
-	STA <btp_mem_pos
+	;STA <btp_mem_pos
+
+	TAY
+	CLC
 
 	LDA #$00
 	STA $4B
@@ -87,9 +91,9 @@ end__:
 	Add_16 >btp_mem_pos, <btp_mem_pos, #<Bitmap, #>Bitmap, !
 
 	;;Let draw some stuff
-	LDX #$00
+	;LDY #$00
 	LDA byte_to_paint ;; note that both bytes are used!
-	ORA (>btp_mem_pos, X)
+	ORA (>btp_mem_pos), Y
-	STA (>btp_mem_pos, X)
+	STA (>btp_mem_pos), Y
 	RTS
 .endproc