EarthBound flag expansion standalone patch

expand_flags.ccs

// expand_flags.ccs - v2 (fixed battle music bug)
// developed by cooprocks123e with code from stochaztic
// bug testing by Messianic
// use it how you want. or don't, that's fine too

import asm65816

define NEW_PERSISTENT_RAM_LOCATION = 0x7EB600
define NEW_PERSISTENT_RAM_SIZE     = 0x9D

define NEW_FLAGS_LOCATION            = 0x7EB600
define NEW_FLAGS_LOCATION_MINUS_0x80 = 0x7EB580 // Must equal (NEW_FLAGS_LOCATION - 0x80)
define NEW_FLAGS_SIZE                = 0x9D
define TOTAL_NUM_FLAG_BYTES          = 0x11D    // Must equal (NEW_FLAGS_SIZE + 0x80)

define SAVEFILE_SIZE                        = 0x550
define SAVEFILE_SIZE_TIMES_2                = 0xAA0
define SAVEFILE_NUM_BYTES_AFTER_HEADER      = 0x530
define SAVEFILE_NUM_WORDS_AFTER_HEADER      = 0x298
define SAVEFILE_NUM_BYTES_USED_AFTER_HEADER = 0x530

//// Expand flags /////////////////////////////////////////////////////////////

ROM[0xc21628] = {
GetEventFlag:
    /* 28 */     REP(0x31)
                 // We can save a lot of space since we don't need a stack frame
    /* 2a */     DEC
    /* 2b */     TAY
                 // Read flag bit from table
    /* 2c */     AND_i(0x0007) // Take flag_index mod 8
    /* 2f */     TAX
    /* 30 */     LDA_xl(0xc4562f)
    /* 34 */     PHA
                 // Calculate flag byte offset
    /* 35 */     TYA
    /* 36 */     LSR
    /* 37 */     LSR
    /* 38 */     LSR
    /* 39 */     TAX
    /* 3a */     PLA
                 // Check if flag number is in range, and return 0 if not
    /* 3b */     CPX_i(TOTAL_NUM_FLAG_BYTES)
    /* 3e */     BMI(3)
    /* 40 */     JMP(0x1659) // GetEventFlag_ReturnZero
                 // Check if flag number is in the new range
    /* 43 */     CPX_i(0x0080)
    /* 46 */     BPL(5)
                 // Load flag from old range
    /* 48 */     AND_x(0x9c08)
    /* 4b */     BRA(3)
                 // Load flag from new range
    /* 4d */     AND_x(NEW_FLAGS_LOCATION_MINUS_0x80)
                 // Mask down to lowest byte
    /* 50 */     AND_i(0x00ff)
    /* 53 */     BEQ(4)
    /* 55 */     LDA_i(0x0001)
    /* 58 */     RTL
             GetEventFlag_ReturnZero:
    /* 59 */     LDA_i(0x0000)
    /* 5c */     RTL
    /* 5d */     RTL // To match up with the previous RTL

SetEventFlag: /* Flag number in A, value in X */
    /* 5e */    REP(0x31)
    /* 60 */    DEC
    /* 61 */    PHA
    /* 62 */    LSR
    /* 63 */    LSR
    /* 64 */    LSR
    /* 65 */    CMP_i(TOTAL_NUM_FLAG_BYTES)
    /* 68 */    BMI(4)
                // It's out of range. Return zero.
    /* 6a */    PLA // Make sure stack is the same as when we got here
    /* 6b */    JMP(0x1659) // GetEventFlag_ReturnZero
    /* 6e */    CMP_i(0x0080)
    /* 71 */    CLC
    /* 72 */    BPL(5)
    /* 74 */    ADC_i(0x9c08)
    /* 77 */    BRA(3)
    /* 79 */    ADC_i(NEW_FLAGS_LOCATION_MINUS_0x80)
    /* 7c */    TAY
    /* 7d */    PLA // A: Flag-1, X: Value, Y: Ptr to flag byte
    /* 7e */    PHX
    /* 7f */    AND_i(0x0007)
    /* 82 */    TAX
    /* 83 */    LDA_xl(0xc4562f)
    /* 87 */    AND_i(0x00ff)
    /* 8a */    PLX
    /* 8b */    BEQ(5)
    /* 8d */    ORA_y(0x0000)
    /* 90 */    BRA(6)
    /* 92 */    EOR_i(0xffff)
    /* 95 */    AND_y(0x0000)
    /* 98 */    STA_y(0x0000)
                // For whatever reason this function returns the modified flag byte
    /* 9b */    AND_i(0x00ff)
    /* 9e */    RTL

    /* 9f */    RTL
    /* a0 */    RTL
    /* a1 */    RTL
    /* a2 */    RTL
    /* a3 */    RTL
    /* a4 */    RTL
    /* a5 */    RTL
    /* a6 */    RTL
    /* a7 */    RTL
    /* a8 */    RTL
    /* a9 */    RTL
    /* aa */    RTL
    /* ab */    RTL
    /* ac */    RTL // Original RTL
}

//// Expand SRAM savefile /////////////////////////////////////////////////////
// Keep the SRAM the same size, but expand each savefile

ROM[0xef05b4] = { short SAVEFILE_SIZE }
ROM[0xef05de] = { short SAVEFILE_SIZE }

ROM[0xef063e] = { short SAVEFILE_SIZE }

ROM[0xef06b9] = { short SAVEFILE_SIZE }
ROM[0xef06e3] = { short SAVEFILE_SIZE }
ROM[0xef072c] = { short SAVEFILE_SIZE }

ROM[0xef073f] = { short SAVEFILE_SIZE }
ROM[0xef0774] = { short SAVEFILE_NUM_BYTES_AFTER_HEADER }

ROM[0xef0786] = { short SAVEFILE_SIZE }
ROM[0xef07b9] = { short SAVEFILE_NUM_WORDS_AFTER_HEADER }

ROM[0xef07dc] = { short SAVEFILE_SIZE }

ROM[0xef08b4] = { short SAVEFILE_SIZE }

ROM[0xef0a73] = { short SAVEFILE_SIZE_TIMES_2 }

ROM[0xef0ba7] = { short SAVEFILE_NUM_BYTES_USED_AFTER_HEADER }
ROM[0xef0bb9] = { short SAVEFILE_NUM_BYTES_USED_AFTER_HEADER }


//// Code from Chaz - thanks! /////////////////////////////////////////////////
// This patches the savegame routines to load/store additional RAM to SRAM.

// Both saving and loading happen in three chunks despite all sections being continuous.
// Add the third chunk to the second, then use the third code to point to new memory.
// New memory in RAM located at 0x7eb600, 77 (0x4d) bytes long. New SRAM block begins 0x4b3.

// Saving function at EF/088F
ROM[0xEF097E] = { LDA_i(0x02BA)                      }    // - existing 0x023A + next section 0x0080
ROM[0xEF0985] = { LDA_i(0x02BA)                      }    //
ROM[0xEF099B] = { LDA_i(NEW_PERSISTENT_RAM_LOCATION) }    // - new memory location (was #$9C08)
ROM[0xEF09DA] = { LDA_i(NEW_PERSISTENT_RAM_SIZE)     }    // - new memory size

// Loading function at EF/0A68
ROM[0xEF0B2D] = { LDA_i(0x02BA)                      }    // - existing 0x023A + next section 0x0080
ROM[0xEF0B34] = { LDA_i(0x02BA)                      }    //
ROM[0xEF0B42] = { LDA_i(NEW_PERSISTENT_RAM_LOCATION) }    // - new memory location (was #$9C08)
ROM[0xEF0B81] = { LDA_i(NEW_PERSISTENT_RAM_SIZE)     }    // - new memory size