Earthbound code to automatically mash when pressing Y, preventing RSI

y_mash.ccs

// Makes holding the Y button equivalent to mashing, in text menus.
// by JTolmar
import asm65816

// Here are the pad constants:
// https://github.com/Herringway/ebsrc/blob/2839456c950dfe51498c04efbdd98198b2051ec7/src/enums.asm#L226
define ABRYS = 0xE0A0 // A, B, R, Y, Select
define ABYS = 0xA0A0 // A, B, R, Select
define Y_ONLY = 0x4000 // Y
// And the pad state in RAM
define PAD_HELD = 0x7E0069
define PAD_PRESS = 0x7E006D

// Define a function that returns true if Y held or the normal ones pressed
MashFunc:
  LDA_a(PAD_HELD)
  AND_i(Y_ONLY)
  BEQ(1)
  RTL
  LDA_a(PAD_PRESS)
  AND_i(ABRYS)
  RTL

// The above function replaces
//   LDA_a(PAD_PRESS)
//   AND_i(ABYS)
// Which is 6 bytes. So this is the replacement
define REPLACE_CHECK = {
  JSL(MashFunc)
  BRA(0) // Equivalent to NOP NOP, but ONE WHOLE CYCLE faster
}

// Here's the waits in the main "wait" function:
// These loops update the blinking triangle.
// I don't know why these are separate; one is a loop inside the other.
// https://github.com/Herringway/ebsrc/blob/2839456c950dfe51498c04efbdd98198b2051ec7/src/text/ccs/halt.asm#L53
// https://github.com/Herringway/ebsrc/blob/2839456c950dfe51498c04efbdd98198b2051ec7/src/text/ccs/halt.asm#L89
ROM[0xC10224] = REPLACE_CHECK
ROM[0xC10278] = REPLACE_CHECK

// This version does not update the blinking triangle.
// https://github.com/Herringway/ebsrc/blob/2839456c950dfe51498c04efbdd98198b2051ec7/src/text/ccs/halt.asm#L129
ROM[0xC101D8] = REPLACE_CHECK

// There's an "interruptable pause" function used in battles which has another:
// (thanks phoenixbound for finding it)
// https://github.com/Herringway/ebsrc/blob/8fc70d03d136c0eb6a19423a45d9f0864cfed19c/src/unknown/C1/C100FE.asm#L14
// https://github.com/Herringway/ebsrc/blob/8fc70d03d136c0eb6a19423a45d9f0864cfed19c/src/unknown/C1/C100FE.asm#L50
ROM[0xC10119] = REPLACE_CHECK
ROM[0xC1015C] = REPLACE_CHECK