fox32rom: Add string_to_int

fox32rom.def

@@ -64,6 +64,9 @@ compare_memory_words:                     jmp [0xF0046010]
 compare_string:                           jmp [0xF0046014]
 string_length:                            jmp [0xF0046018]
 
+; integer jump table
+string_to_int:                            jmp [0xF0047000]
+
 ; event types
 const EVENT_TYPE_MOUSE_CLICK:    0x00000000
 const EVENT_TYPE_MOUSE_RELEASE:  0x00000001

integer.asm

@@ -0,0 +1,63 @@
+; integer routines
+
+; convert ASCII string into an integer
+; thanks to lua for helping with this :3
+; inputs:
+; r0: pointer to null-terminated string
+; r1: radix (i.e. 10 for decimal, 16 for hexadecimal)
+; outputs:
+; r0: integer
+string_to_int:
+    push r2
+    push r3
+    mov r3, 0
+string_to_int_loop:
+    movz.8 r2, [r0]
+    inc r0
+
+    cmp r2, 0
+    ifz jmp string_to_int_end
+
+    ; if (digit >= '0' && digit <= '9') {
+    ;     digit -= '0';
+    ; } else if (digit >= 'A' && digit <= 'Z') {
+    ;     digit -= 'A' - 10
+    ; } else if (digit >= 'a' && digit <= 'z') {
+    ;     digit -= 'a' - 10
+    ; } else {
+    ;     continue;
+    ; }
+
+    cmp r2, '0'
+    iflt jmp string_to_int_loop_2
+    cmp r2, '9'
+    ifgt jmp string_to_int_loop_2
+
+    sub r2, '0'
+    jmp string_to_int_loop_end
+string_to_int_loop_2:
+    cmp r2, 'A'
+    iflt jmp string_to_int_loop_3
+    cmp r2, 'Z'
+    ifgt jmp string_to_int_loop_3
+
+    sub r2, 0x37 ; 'A' - 10
+    jmp string_to_int_loop_end
+string_to_int_loop_3:
+    cmp r2, 'a'
+    iflt jmp string_to_int_loop
+    cmp r2, 'z'
+    ifgt jmp string_to_int_loop
+
+    sub r2, 0x57 ; 'a' - 10
+string_to_int_loop_end:
+    mul r3, r1
+    add r3, r2
+    jmp string_to_int_loop
+string_to_int_end:
+    mov r0, r3
+
+    pop r3
+    pop r2
+    ret
+

main.asm

@@ -124,6 +124,7 @@ get_rom_version:
     #include "draw_rectangle.asm"
     #include "draw_text.asm"
     #include "event.asm"
+    #include "integer.asm"
     #include "keyboard.asm"
     #include "memory.asm"
     #include "menu.asm"
@@ -210,6 +211,11 @@ get_rom_version:
     data.32 compare_memory_bytes
     data.32 compare_memory_words
     data.32 compare_string
+    data.32 string_length
+
+    ; integer jump table
+    org.pad 0xF0047000
+    data.32 string_to_int
 
     org.pad 0xF004F000
 standard_font_width: