Only re-render PSI help on button press

Without this, the game will constantly try to clear+render the whole PSI
help window per frame which causes extreme lag and tearing.

m2-hack.asm

@@ -48,6 +48,9 @@ incsrc m2-status-switch.asm
 org $80BACFC; bl m2_vwf_entries.bac18_redraw_status
 org $80BADE6; bl m2_vwf_entries.bac18_redraw_status
 org $80BACEE; bl m2_vwf_entries.bac18_clear_psi
+org     $80BADC8
+bl      m2_vwf_entries.bac18_check_button
+b       $80BADD8
 
 //---------------------------------------------------------
 // C1FBC hacks (PSI window)

m2-vwf-entries.asm

@@ -359,3 +359,32 @@ pop     {r0}
 lsl     r0,r0,#0x10
 asr     r4,r0,#0x10
 pop     {pc}
+
+//==============================================================================
+// Only clear+redraw the PSI help if a button has been pressed
+.bac18_check_button:
+push    {lr}
+
+// Copy the thing that was on the stack from the caller
+add     sp,#-4
+ldr     r0,[sp,#8]
+str     r0,[sp,#0]
+
+ldr     r0,=#0x3002500
+ldrh    r0,[r0,#0]
+cmp     r0,#0
+beq     +
+
+// Clear window
+ldr     r0,[r5,#0x28]
+mov     r1,r2
+mov     r2,#0
+bl      $80BE458
+
+// Render window
+ldr     r0,[r5,#0x28]
+bl      $80C8BE4
+
++
+add     sp,#4
+pop     {pc}