Use the memory allocator for tasks' code memory

kernel/main.asm

@@ -9,8 +9,6 @@ const FOX32OS_VERSION_PATCH: 0
 const BACKGROUND_COLOR: 0xFF674764
 const TEXT_COLOR:       0xFFFFFFFF
 
-const STARTUP_TASK_LOAD_ADDRESS: 0x03000000
-
     jmp entry
 
 jump_table:
@@ -75,26 +73,36 @@ entry:
     cmp r0, 0
     ifz jmp boot_disk_1
 
-    ; read the startup file into memory starting at STARTUP_TASK_LOAD_ADDRESS
+    ; allocate memory for the startup file
+    mov r0, startup_file_struct
+    call ryfs_get_size
+    call allocate_memory
+    cmp r0, 0
+    ifz jmp memory_error
+
+    ; read the startup file into memory
+    mov r1, r0
     mov r0, startup_file_struct
-    mov r1, STARTUP_TASK_LOAD_ADDRESS
     call ryfs_read_whole_file
 
     ; relocate and execute it as a new task
 run_startup_task:
-    mov r0, STARTUP_TASK_LOAD_ADDRESS
+    mov r0, r1
     call parse_fxf_binary
+    mov r3, r1
     mov r1, r0
     mov r0, 0
     mov r2, rsp
     sub r2, 4
     call new_task
 
-    ; when the startup file yields for the first time, we'll end up back here
+    ; when the startup file yields for the first time, we'll end up back here.
-    ; jump back to it without adding this "task" (not really a task) into the queue
+    ; jump back to it without adding this "task" (not really a task) into the queue.
-    ; end_current_task_no_mark is used specifically because it doesn't mark the current task (still set to 0) as unused
+    ; end_current_task_no_mark_no_free is used specifically because it doesn't mark
-    ; this does not return
+    ;   the current task (still set to 0) as unused, and it doesn't free the memory
-    call end_current_task_no_mark
+    ;   block.
+    ; this does not return.
+    call end_current_task_no_mark_no_free
 
 ; if startup.cfg is invalid, try loading the raw contents of disk 1 as an FXF binary
 ; if disk 1 is not inserted, then fail
@@ -105,12 +113,21 @@ boot_disk_1:
     ifz jmp startup_error
 
     ; a disk is inserted, load it!!
+
+    ; allocate memory for the startup file
+    ; r31 contains disk size
+    mov r0, r31
+    call allocate_memory
+    cmp r0, 0
+    ifz jmp memory_error
+
     div r31, 512
     inc r31
 
+    mov r2, r0         ; destination pointer
+    mov r5, r0
     mov r0, 0          ; sector counter
-    mov r2, STARTUP_TASK_LOAD_ADDRESS ; destination pointer
+    mov r3, 0x80003001 ; command to read a sector from disk 1 into memory
-    mov r3, 0x80003001 ; command to read a sector from disk 01 into memory
     mov r4, 0x80002000 ; command to set the location of the buffer
 boot_disk_1_loop:
     out r4, r2         ; set the memory buffer location
@@ -119,6 +136,7 @@ boot_disk_1_loop:
     add r2, 512        ; increment the destination pointer
     loop boot_disk_1_loop
 
+    mov r1, r5
     jmp run_startup_task
 
 startup_error:
@@ -136,6 +154,21 @@ startup_error:
     call draw_format_str_to_background
     rjmp 0
 
+memory_error:
+    mov r0, BACKGROUND_COLOR
+    call fill_background
+
+    mov r0, memory_error_str
+    mov r1, 16
+    mov r2, 464
+    mov r3, TEXT_COLOR
+    mov r4, 0x00000000
+    mov r10, FOX32OS_VERSION_MAJOR
+    mov r11, FOX32OS_VERSION_MINOR
+    mov r12, FOX32OS_VERSION_PATCH
+    call draw_format_str_to_background
+    rjmp 0
+
 get_os_version:
     mov r0, FOX32OS_VERSION_MAJOR
     mov r1, FOX32OS_VERSION_MINOR
@@ -148,6 +181,7 @@ get_os_version:
 
 startup_str: data.str "fox32 - OS version %u.%u.%u" data.8 0
 startup_error_str: data.str "fox32 - OS version %u.%u.%u - startup.cfg is invalid!" data.8 0
+memory_error_str: data.str "fox32 - OS version %u.%u.%u - not enough memory to load startup file!" data.8 0
 
 startup_file: data.str "startup cfg"
 startup_file_struct: data.32 0 data.32 0

kernel/task.asm

@@ -3,17 +3,21 @@
 ; add a new task to the queue and jump to it immediately
 ; inputs:
 ; r0: task ID
-; r1: task instruction pointer
+; r1: pointer to task code
-; r2: task stack pointer
+; r2: pointer to task stack
+; r3: pointer to memory block to free when task ends
 ; outputs:
 ; none
 new_task:
-    bse [task_id_bitmap], r0 ; mark this task ID as used
+    ; mark this task ID as used
+    bse [task_id_bitmap], r0
 
-    mov r4, r2
+    mov r4, r2 ; stack pointer
-    mov r3, r1
+    mov r5, r3 ; memory block pointer
-    mov r2, r0
+    mov r3, r1 ; instruction pointer
+    mov r2, r0 ; task ID
 
+    ; add to the queue
     mov r0, [task_queue_ptr]
     call task_store
     mov [task_queue_ptr], r0
@@ -38,6 +42,7 @@ yield_task:
     jmp yield_task_0
 
 ; switch to the next task without adding the current task back into the queue
+; this will automatically free the task's code block
 ; inputs:
 ; none
 ; outputs:
@@ -46,7 +51,9 @@ end_current_task:
     mov r0, current_task ; get the current task struct
     call task_load
     bcl [task_id_bitmap], r2 ; mark this task ID as unused
-end_current_task_no_mark:
+    mov r0, r5 ; memory block pointer
+    call free_memory
+end_current_task_no_mark_no_free:
     pop r0 ; pop the return address off of the stack
 
     cmp [task_queue_ptr], task_queue_bottom
@@ -104,6 +111,8 @@ task_load:
     add r0, 4
     mov r4, [r0] ; stack pointer
     add r0, 4
+    mov r5, [r0] ; memory block pointer
+    add r0, 4
     ret
 
 task_store:
@@ -113,6 +122,8 @@ task_store:
     add r0, 4
     mov [r0], r4 ; stack pointer
     add r0, 4
+    mov [r0], r5 ; memory block pointer
+    add r0, 4
     ret
 
 task_empty:
@@ -123,43 +134,12 @@ task_empty:
 
 task_panic_str: data.str "Task queue empty! Hanging here" data.8 10 data.8 0
 
-const TASK_SIZE: 12
+const TASK_SIZE: 16
 task_id_bitmap: data.32 0
 current_task:
     data.32 0 ; task ID
     data.32 0 ; instruction pointer
     data.32 0 ; stack pointer
+    data.32 0 ; memory block pointer
 task_queue_ptr: data.32 task_queue_bottom
-task_queue_bottom:
+task_queue_bottom: data.fill 0, 512 ; 32 tasks * 4 entries per task * 4 bytes per word = 512
-    data.32 0 data.32 0 data.32 0
-    data.32 0 data.32 0 data.32 0
-    data.32 0 data.32 0 data.32 0
-    data.32 0 data.32 0 data.32 0
-    data.32 0 data.32 0 data.32 0
-    data.32 0 data.32 0 data.32 0
-    data.32 0 data.32 0 data.32 0
-    data.32 0 data.32 0 data.32 0
-    data.32 0 data.32 0 data.32 0
-    data.32 0 data.32 0 data.32 0
-    data.32 0 data.32 0 data.32 0
-    data.32 0 data.32 0 data.32 0
-    data.32 0 data.32 0 data.32 0
-    data.32 0 data.32 0 data.32 0
-    data.32 0 data.32 0 data.32 0
-    data.32 0 data.32 0 data.32 0
-    data.32 0 data.32 0 data.32 0
-    data.32 0 data.32 0 data.32 0
-    data.32 0 data.32 0 data.32 0
-    data.32 0 data.32 0 data.32 0
-    data.32 0 data.32 0 data.32 0
-    data.32 0 data.32 0 data.32 0
-    data.32 0 data.32 0 data.32 0
-    data.32 0 data.32 0 data.32 0
-    data.32 0 data.32 0 data.32 0
-    data.32 0 data.32 0 data.32 0
-    data.32 0 data.32 0 data.32 0
-    data.32 0 data.32 0 data.32 0
-    data.32 0 data.32 0 data.32 0
-    data.32 0 data.32 0 data.32 0
-    data.32 0 data.32 0 data.32 0
-    data.32 0 data.32 0 data.32 0