# HG changeset patch
# User Paul Boddie <paul@boddie.org.uk>
# Date 1435430131 -7200
# Node ID 67e61de96a24c8fb5d099bd09ab70ee371547342
# Parent  d7d91332b0aa73a7cffe57cfeeef04559042f13f
Fixed new task addition, actually scanning the table.
Added locks around table modification operations.
Added task removal support.

diff -r d7d91332b0aa -r 67e61de96a24 switcher.oph
--- a/switcher.oph	Sat Jun 27 20:01:40 2015 +0200
+++ b/switcher.oph	Sat Jun 27 20:35:31 2015 +0200
@@ -36,8 +36,10 @@
     jsr new_task
     .invoke store16 second_task, $76
     jsr new_task
-test:
-    jmp test
+    .invoke store16 third_task, $76
+    jsr new_task
+wait:
+    jmp wait ; wait for the switcher to take over
 
 
 
@@ -209,6 +211,8 @@
     ; check the MSB of each task table entry
 
     ldy #1
+
+check_new_task:
     lda tasks, y
     cmp #0
     beq add_new_task
@@ -219,16 +223,19 @@
 
     cpy #TASK_TABLE_LENGTH
     bpl no_new_task
+    jmp check_new_task
 
 add_new_task:
 
     ; copy the task structure location to the table
 
+    sei
     lda $77
     sta tasks, y
     dey
     lda $76
     sta tasks, y
+    cli
 
     lda #0
     rts
@@ -239,6 +246,25 @@
 
 
 
+; remove a task from the table
+;
+; A: task offset
+; affects: A, Y
+
+remove_task:
+
+    ; zero out the table entry
+
+    tay
+    sei
+    lda #0
+    sta tasks, y
+    iny
+    sta tasks, y
+    cli
+    rts
+
+
 ; example tasks
 
 first_task:
@@ -263,4 +289,29 @@
     .invoke add16 1, $7008
     jmp second_task_start
 
+
+
+third_task:
+    .byte 0 ; currently unused
+    .byte 0 ; currently unused
+    .byte 0 ; currently unused
+    .byte 0 ; saved flags
+    .word third_task_start ; saved PC
+third_task_start:
+    .invoke store16 0, $7010
+    ldx #0
+_loop:
+    lda $7010
+    cmp #$ff
+    bne _continue
+    lda $7011
+    cmp #$ff
+    bne _continue
+    txa
+    jsr remove_task
+    inx
+_continue:
+    .invoke add16 1, $7010
+    jmp _loop
+
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