Assembler code
.C0:0019 .A8
.C0:0019 .I16
.C0:0019 ; ds=0 B=0 e=0
.C0:0019
.C0:0019 ; =============== S U B R O U T I N E =======================================
.C0:0019
.C0:0019
.C0:0019 sub_C00019: ; CODE XREF: Emulation_mode_RESET+3↓J
.C0:0019
.C0:0019 ; FUNCTION CHUNK AT .C0:C62B SIZE 00000088 BYTES
.C0:0019
.C0:0019 SEI
.C0:001A CLC
.C0:001B XCE
.C0:001C SEP #$20 ; ' '
.C0:001E REP #$10
.C0:0020 LDX #$15FF
.C0:0023 TXS
.C0:0024 LDX #0
.C0:0027 PHX
.C0:0028 PLD
.C0:0029 TDC
.C0:002A PHA
.C0:002B PLB
.C0:002C LDA #1
.C0:002E STA MEMSEL ; Memory-2 Waitstate Control (0000000a a: 0 = 2.68 MHz, 1 = 3.58 MHz
.C0:0031 STZ MDMAEN ; Select General Purpose DMA Channel(s) and Start Transfer (abcdefgh a = Channel 7...h = Channel 0: 1 = Enable 0 = Disable
.C0:0034 STZ HDMAEN ; Select H-Blank DMA (H-DMA) Channel(s) (abcdefgh a = Channel 7 .. h = Channel 0: 1 = Enable 0 = Disable
.C0:0037 LDA #$8F
.C0:0039 STA INIDISP ; Display Control 1 (a000bbbb a: 0=screen on 1=screen off, b = brightness)
.C0:003C STZ NMITIMEN ; Interrupt Enable and Joypad Request (a0bc000d a = NMI b = V-Count c = H-Count d = Joypad)
.C0:003F JSR sub_C00525
.C0:0042 LDX #0
.C0:0045 STX D, word_7E0000
.C0:0047 LDX #$FFFF