Allow starting multiple FXF binaries at startup

kernel/main.asm

@@ -58,16 +58,18 @@ entry:
     call draw_format_str_to_background
 
     ; open startup.cfg
-    mov r0, startup_file
+    mov r0, startup_cfg
     mov r1, 0
-    mov r2, startup_file_struct
+    mov r2, startup_cfg_struct
     call ryfs_open
     cmp r0, 0
     ifz jmp boot_disk_1
 
-    ; load the first 11 bytes of startup.cfg, overwriting the "startup cfg" string
+    ; load a startup task
+load_startup_task:
+    ; load 11 bytes of startup.cfg into startup_file
     mov r0, 11
-    mov r1, startup_file_struct
+    mov r1, startup_cfg_struct
     mov r2, startup_file
     call ryfs_read
 
@@ -85,25 +87,54 @@ entry:
     call allocate_memory
     cmp r0, 0
     ifz jmp memory_error
+    mov [startup_file_binary_ptr], r0
+
+    ; allocate 64KiB for the startup file's stack
+    mov r0, 65536
+    call allocate_memory
+    cmp r0, 0
+    ifz jmp memory_error
+    mov [startup_file_stack_ptr], r0
 
     ; read the startup file into memory
-    mov r1, r0
     mov r0, startup_file_struct
+    mov r1, [startup_file_binary_ptr]
     call ryfs_read_whole_file
 
     ; relocate and execute it as a new task
-run_startup_task:
     mov r0, r1
     call parse_fxf_binary
     mov r3, r1
     mov r1, r0
-    mov r0, 0
+    movz.8 r0, [next_task_id]
-    mov r2, rsp
+    mov r2, [startup_file_stack_ptr]
+    add r2, 65536
     sub r2, 4
-    mov r4, 0 ; don't attempt to free any stack block if the task ends
+    mov r4, [startup_file_stack_ptr]
     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
+    ; now, check to see if startup.cfg has any other entries
+    ; we do this by checking to see if the size of startup.cfg is less than or equal to 12 * next_task_id bytes
+    inc.8 [next_task_id]
+    mov r0, startup_cfg_struct
+    call ryfs_get_size
+    movz.8 r1, [next_task_id]
+    mul r1, 12
+    cmp r0, r1
+    iflteq jmp no_other_tasks
+
+    ; seek forward one byte to skip the linefeed
+    mov r0, startup_cfg_struct
+    call ryfs_tell
+    inc r0
+    mov r1, startup_cfg_struct
+    call ryfs_seek
+
+    ; load the next task
+    jmp load_startup_task
+
+no_other_tasks:
     ; jump back to it without adding this "task" (not really a task) into the queue.
     ; end_current_task_no_mark_no_free is used specifically because it doesn't mark
     ;   the current task (still set to 0) as unused, and it doesn't free the memory
@@ -144,7 +175,16 @@ boot_disk_1_loop:
     loop boot_disk_1_loop
 
     mov r1, r5
-    jmp run_startup_task
+    mov r0, r5
+    call parse_fxf_binary
+    mov r3, r1
+    mov r1, r0
+    movz.8 r0, [next_task_id]
+    mov r2, rsp
+    sub r2, 4
+    mov r4, 0 ; don't attempt to free any stack block if the task ends
+    call new_task
+    call end_current_task_no_mark_no_free
 
 startup_error:
     mov r0, BACKGROUND_COLOR
@@ -188,10 +228,15 @@ 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
+memory_error_str: data.str "fox32 - OS version %u.%u.%u - not enough memory to perform operation!" data.8 0
 
-startup_file: data.str "startup cfg"
+next_task_id: data.8 0
+startup_cfg: data.str "startup cfg"
+startup_cfg_struct: data.32 0 data.32 0
+startup_file: data.str "           "
 startup_file_struct: data.32 0 data.32 0
+startup_file_binary_ptr: data.32 0
+startup_file_stack_ptr: data.32 0
 
     #include "../../fox32rom/fox32rom.def"