fox32rom: Add read_sector and write_sector

disk.asm

@@ -0,0 +1,43 @@
+; disk routines
+
+; read a sector into the specified memory buffer
+; inputs:
+; r0: sector number
+; r1: disk ID
+; r2: sector buffer (512 bytes)
+; outputs:
+; none
+read_sector:
+    push r3
+    push r4
+
+    mov r3, 0x80002000       ; command to set the location of the buffer
+    mov r4, 0x80003000       ; command to read a sector from a disk into the buffer
+    or.8 r4, r1              ; set the disk ID
+    out r3, r2               ; set the memory buffer location
+    out r4, r0               ; read the sector into memory
+
+    pop r4
+    pop r3
+    ret
+
+; wrtie a sector from the specified memory buffer
+; inputs:
+; r0: sector number
+; r1: disk ID
+; r2: sector buffer (512 bytes)
+; outputs:
+; none
+write_sector:
+    push r3
+    push r4
+
+    mov r3, 0x80002000       ; command to set the location of the buffer
+    mov r4, 0x80004000       ; command to write a sector to a disk from the buffer
+    or.8 r4, r1              ; set the disk ID
+    out r3, r2               ; set the memory buffer location
+    out r4, r0               ; write the sector from memory
+
+    pop r4
+    pop r3
+    ret

fox32rom.def

@@ -45,6 +45,10 @@ draw_menu_items:                          jmp [0xF0044014]
 close_menu:                               jmp [0xF0044018]
 menu_update_event:                        jmp [0xF004401C]
 
+; disk jump table
+read_sector:                              jmp [0xF0045000]
+write_sector:                             jmp [0xF0045004]
+
 ; event types
 const MOUSE_CLICK_EVENT_TYPE:    0x00000000
 const MENU_BAR_CLICK_EVENT_TYPE: 0x00000001

main.asm

@@ -127,6 +127,7 @@ get_rom_version:
     #include "background.asm"
     #include "boot.asm"
     #include "debug.asm"
+    #include "disk.asm"
     #include "draw_rectangle.asm"
     #include "draw_text.asm"
     #include "event.asm"
@@ -194,6 +195,11 @@ get_rom_version:
     data.32 close_menu
     data.32 menu_update_event
 
+    ; disk jump table
+    org.pad 0xF0045000
+    data.32 read_sector
+    data.32 write_sector
+
     org.pad 0xF004F000
 standard_font_width:
     data.16 8