kernel: Add :ramdisk stream

kernel/main.asm

@@ -74,6 +74,7 @@ jump_table:
     data.32 get_size
     data.32 create
     data.32 delete
+    data.32 copy
 
     ; widget jump table
     org.pad 0x00000610

kernel/vfs/ramdisk.asm

@@ -0,0 +1,94 @@
+; disk vfs stream routines
+
+ramdisk_vfs_stream_name: data.strz "ramdisk"
+
+; open a disk id 5 stream
+; inputs:
+; r2: file struct: pointer to a blank file struct (stream)
+; outputs:
+; r0: non-zero
+open_stream_ramdisk:
+    push r2
+
+    mov.8 [r2], 0                  ; write file_reserved_1
+    inc r2
+    mov.16 [r2], 0                 ; write file_reserved_2
+    add r2, 2
+    mov [r2], 0                    ; write file_seek_offset
+    add r2, 4
+    mov.8 [r2], 1                  ; write file_system_type
+    inc r2
+    mov [r2], ramdisk_stream_read  ; write file_read_call
+    add r2, 4
+    mov [r2], ramdisk_stream_write ; write file_write_call
+    add r2, 4
+    mov [r2], 0x00800000           ; write file_size
+    add r2, 4
+    mov [r2], 0                    ; write file_reserved_3
+    add r2, 4
+    mov [r2], 0                    ; write file_reserved_4
+    add r2, 4
+    mov [r2], 0                    ; write file_reserved_5
+
+    pop r2
+    mov r0, 1
+    ret
+
+; read a byte from disk 5
+; inputs:
+; r0: seek offset
+; outputs:
+; r0: byte
+ramdisk_stream_read:
+    push r1
+    push r2
+
+    push r0
+    div r0, 512
+    mov r1, 5
+    mov r2, TEMP_SECTOR_BUF
+    call read_sector
+    pop r0
+    rem r0, 512
+    add r0, TEMP_SECTOR_BUF
+    movz.8 r0, [r0]
+
+    pop r2
+    pop r1
+    ret
+
+; write a byte to disk 5
+; inputs:
+; r0: pointer to source buffer
+; r1: seek offset
+; outputs:
+; none
+ramdisk_stream_write:
+    push r1
+    push r2
+    push r3
+
+    push r0
+    push r1
+    push r1
+    div r1, 512
+    mov r0, r1
+    mov r1, 5
+    mov r2, TEMP_SECTOR_BUF
+    call read_sector
+    pop r1
+    pop r3
+    pop r0
+    rem r1, 512
+    add r1, TEMP_SECTOR_BUF
+    mov.8 [r1], [r0]
+    mov r0, r3
+    div r0, 512
+    mov r1, 5
+    mov r2, TEMP_SECTOR_BUF
+    call write_sector
+
+    pop r3
+    pop r2
+    pop r1
+    ret

kernel/vfs/vfs.asm

@@ -85,6 +85,12 @@ open_stream:
     ifz pop r1
     ifz jmp open_stream_ofb
 
+    ; ramdisk
+    mov r1, ramdisk_vfs_stream_name
+    call compare_string
+    ifz pop r1
+    ifz jmp open_stream_ramdisk
+
     ; romdisk
     mov r1, romdisk_vfs_stream_name
     call compare_string
@@ -129,6 +135,38 @@ delete:
     ifz ret
     jmp ryfs_delete
 
+; copy a file's contents
+; inputs:
+; r0: source file struct: pointer to a filled file struct
+; r1: destination file struct: pointer to a filled file struct
+; outputs:
+; none
+copy:
+    mov [copy_source_struct_ptr], r0
+    mov [copy_dest_struct_ptr], r1
+    call get_size
+    mov [copy_buffer_size], r0
+    call allocate_memory
+    mov [copy_buffer_ptr], r0
+
+    mov r0, [copy_buffer_size]
+    mov r1, [copy_source_struct_ptr]
+    mov r2, [copy_buffer_ptr]
+    call read
+    mov r0, [copy_buffer_size]
+    mov r1, [copy_dest_struct_ptr]
+    mov r2, [copy_buffer_ptr]
+    call write
+
+    mov r0, [copy_buffer_ptr]
+    call free_memory
+
+    ret
+copy_source_struct_ptr: data.32 0
+copy_dest_struct_ptr: data.32 0
+copy_buffer_ptr: data.32 0
+copy_buffer_size: data.32 0
+
 ; seek specified file to the specified offset
 ; inputs:
 ; r0: byte offset
@@ -394,5 +432,6 @@ convert_filename_output_string: data.fill 0, 12
     #include "vfs/disk3.asm"
     #include "vfs/fb.asm"
     #include "vfs/ofb.asm"
+    #include "vfs/ramdisk.asm"
     #include "vfs/romdisk.asm"
     #include "vfs/serial.asm"