kernel + sh: Theoretically support FXF binaries with a bss section

applications/sh/launch.asm

@@ -1,5 +1,8 @@
 ; FXF launcher helper routines
 
+; FIXME: this should really use the `launch_fxf_from_open_file` routine
+;        it will need some work to ensure things like the debug prefix works though
+
 ; launch an FXF binary from a shell entry
 ; inputs:
 ; r0: pointer to FXF binary name
@@ -65,9 +68,32 @@ launch_fxf_name_loop_done:
     cmp r0, 0
     ifz ret
 
+    ; if this is not FXF version 0, then there is a bss section
+    mov r0, 3
+    mov r1, launch_fxf_struct
+    call seek
+    mov r0, 1
+    mov r1, launch_fxf_struct
+    mov r2, launch_fxf_temp
+    call read
+    cmp.8 [launch_fxf_temp], 0
+    ifz mov [launch_fxf_temp], 0
+    ifz jmp launch_fxf_continue
+    mov r0, 0x14
+    mov r1, launch_fxf_struct
+    call seek
+    mov r0, 4
+    mov r1, launch_fxf_struct
+    mov r2, launch_fxf_temp
+    call read
+launch_fxf_continue:
+    mov r0, 0
+    mov r1, launch_fxf_struct
+    call seek
     ; allocate memory for the binary
     mov r0, launch_fxf_struct
     call get_size
+    add r0, [launch_fxf_temp] ; add bss size found above
     call allocate_memory
     cmp r0, 0
     ifz jmp allocate_error
@@ -164,6 +190,7 @@ launch_fxf_struct: data.fill 0, 32
 launch_fxf_task_id: data.8 0
 launch_fxf_binary_ptr: data.32 0
 launch_fxf_stack_ptr: data.32 0
+launch_fxf_temp: data.32 0
 
 launch_fxf_yield_should_suspend: data.8 0
 launch_fxf_debug_mode: data.8 0

kernel/fxf/FXF specification.md

@@ -1,8 +1,9 @@
-| Byte Range            | Description                |
-| :-------------------: | -------------------------- |
-| 0x00000000-0x00000002 | "FXF" magic bytes          |
-| 0x00000003            | header version (must be 0) |
-| 0x00000004-0x00000007 | code size                  |
-| 0x00000008-0x0000000B | pointer to code            |
-| 0x0000000C-0x0000000F | reloc table size           |
-| 0x00000010-0x00000013 | pointer to reloc table     |
+| Byte Range            | Description                             |
+| :-------------------: | --------------------------------------- |
+| 0x00000000-0x00000002 | "FXF" magic bytes                       |
+| 0x00000003            | header version (0 for no bss, else bss) |
+| 0x00000004-0x00000007 | code size                               |
+| 0x00000008-0x0000000B | pointer to code                         |
+| 0x0000000C-0x0000000F | reloc table size                        |
+| 0x00000010-0x00000013 | pointer to reloc table                  |
+| 0x00000014-0x00000017 | bss allocation size (if version != 0)   |

kernel/fxf/fxf.asm

@@ -7,18 +7,20 @@
 ; r0: relocation address or 0 on error
 parse_fxf_binary:
     push r1
-    mov r1, [r0]
-    cmp r1, [fxf_magic]
-    ifnz pop r1
+    push r2
+    mov r1, fxf_magic
+    mov r2, 3
+    call compare_memory_bytes
+    pop r2
+    pop r1
     ifnz mov r0, 0
     ifnz ret
-    pop r1
 
     call fxf_reloc
 
     ret
 
-fxf_magic: data.strz "FXF"
+fxf_magic: data.str "FXF"
 
     #include "fxf/launch.asm"
     #include "fxf/reloc.asm"
@@ -27,3 +29,4 @@ const FXF_CODE_SIZE:   0x00000004
 const FXF_CODE_PTR:    0x00000008
 const FXF_RELOC_SIZE:  0x0000000C
 const FXF_RELOC_PTR:   0x00000010
+const FXF_BSS_SIZE:    0x00000014

kernel/fxf/launch.asm

@@ -60,9 +60,32 @@ launch_fxf_from_disk:
     cmp r0, 0
     ifz jmp launch_fxf_from_disk_file_error
 launch_fxf_from_open_file_1:
+    ; if this is not FXF version 0, then there is a bss section
+    mov r0, 3
+    mov r1, [launch_fxf_struct_ptr]
+    call seek
+    mov r0, 1
+    mov r1, [launch_fxf_struct_ptr]
+    mov r2, launch_fxf_bss_size
+    call read
+    cmp.8 [launch_fxf_bss_size], 0
+    ifz mov [launch_fxf_bss_size], 0
+    ifz jmp launch_fxf_continue
+    mov r0, FXF_BSS_SIZE
+    mov r1, [launch_fxf_struct_ptr]
+    call seek
+    mov r0, 4
+    mov r1, [launch_fxf_struct_ptr]
+    mov r2, launch_fxf_bss_size
+    call read
+launch_fxf_continue:
+    mov r0, 0
+    mov r1, [launch_fxf_struct_ptr]
+    call seek
     ; allocate memory for the binary
     mov r0, [launch_fxf_struct_ptr]
     call get_size
+    add r0, [launch_fxf_bss_size]
     call allocate_memory
     cmp r0, 0
     ifz jmp launch_fxf_from_disk_allocate_error
@@ -165,6 +188,7 @@ launch_fxf_struct: data.fill 0, 32
 launch_fxf_task_id: data.8 0
 launch_fxf_binary_ptr: data.32 0
 launch_fxf_stack_ptr: data.32 0
+launch_fxf_bss_size: data.32 0
 launch_fxf_allocate_error_string1: data.strz "Failed to allocate memory for a new task"
 launch_fxf_allocate_error_string2: data.strz "The memory allocator seems to be in an"
 launch_fxf_allocate_error_string3: data.strz "invalid state, a reboot is recommended"