From 3c6a583190b827c0e88e535d486a4f191ee255c0 Mon Sep 17 00:00:00 2001
From: Miquel Sabaté Solà <msabate@suse.com>
Date: Tue, 2 Apr 2024 23:49:52 +0200
Subject: Add a way to safely read from controllers
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First of all, move some reading utilities into the new `shared`
directory, so controllers can be read by more than one example. Second,
even if we keep the example on `basics/input.s` simple, let's provide a
safe alternative for the other examples.

Signed-off-by: Miquel Sabaté Solà <msabate@suse.com>
---
 scroll/include/joypad.s | 63 -------------------------------------------------
 1 file changed, 63 deletions(-)
 delete mode 100644 scroll/include/joypad.s

(limited to 'scroll/include')

diff --git a/scroll/include/joypad.s b/scroll/include/joypad.s
deleted file mode 100644
index 8711c28..0000000
--- a/scroll/include/joypad.s
+++ /dev/null
@@ -1,63 +0,0 @@
-.segment "CODE"
-
-;;;
-;; Joypad controller code. The following memory addresses are reserved: $21-$23.
-;;
-;; Memory address $21 is used for internal purposes, whereas $22 and $23 contain
-;; the bitmask of the buttons that are pressed from each controller.
-;;;
-
-.scope Joypad
-    ;; Button masks.
-    BUTTON_A      = 1 << 7
-    BUTTON_B      = 1 << 6
-    BUTTON_SELECT = 1 << 5
-    BUTTON_START  = 1 << 4
-    BUTTON_UP     = 1 << 3
-    BUTTON_DOWN   = 1 << 2
-    BUTTON_LEFT   = 1 << 1
-    BUTTON_RIGHT  = 1 << 0
-
-    ;; Port addresses for controllers.
-    JOYPAD1 = $4016
-    JOYPAD2 = $4017
-
-    ;; We keep all the information from controller from mainly two variables:
-    ;; m_buttons1 and m_buttons2; containing respectively the buttons pressed
-    ;; for this frame for both controllers. The m_inv_buttons ($21) is an
-    ;; internal variable and should not be used for anything outside of this
-    ;; usage.
-    m_inv_buttons = $21
-    m_buttons1    = $22
-    m_buttons2    = $23
-
-    ;; READ_CONTROLLER reads the input from the controller mapped into the given
-    ;; port, and saves the state into the given `buttons` address.
-    ;; Implementation taken from NESHacker's example of smb3-like movement.
-    .macro READ_CONTROLLER port, buttons
-        lda m_inv_buttons
-        tay
-        lda #1
-        sta port
-        sta m_inv_buttons
-        lsr
-        sta port
-    :
-        lda port
-        lsr
-        rol m_inv_buttons
-        bcc :-
-        tya
-        eor m_inv_buttons
-        and m_inv_buttons
-        sta buttons
-    .endmacro
-
-    ;; read sets the values for m_buttons1 and m_buttons2 as read from both
-    ;; controllers.
-    .proc read
-        READ_CONTROLLER JOYPAD1, m_buttons1
-        READ_CONTROLLER JOYPAD2, m_buttons2
-        rts
-    .endproc
-.endscope
-- 
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