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#810

Sub-zero 01

Sub-zero

4.593 lines of code

RasterbarsRSTRMusicSIDScrollerSCRLSpritesSPRTBitmapBMAP
Disassemble Download .asm Download .prg intros.c64.org

History

Released
October 1988
Code
Toy (Roy Fielding)
Music
Toy (Roy Fielding) — "Subzero Intro"
Group
Sub-Zero — United Kingdom, founded April 1988

This crack intro from Sub-Zero is documented on CSDb (release ID 106108) as dating from October 1988. The code is credited to Toy — real name Roy Fielding — who also composed the accompanying SID tune, catalogued in the High Voltage SID Collection under the path /MUSICIANS/T/Toy/Subzero_Intro.sid. Sub-Zero was a British group founded in April 1988 by Toy, Bear, Jog, and Wiz, all of whom had left Pulsar to establish the new outfit. CSDb (group ID 2361) classifies Sub-Zero as both a demo group and a cracker group, but their run was short-lived — by February 1989 the group was reported dead, with all members having departed. Toy served as the group’s primary creative force, contributing code, graphics, and music. The group produced multiple crack intros during its brief existence, with at least four documented on CSDb.

Sources: CSDb · CSDb · intros.c64.org

subzero-01.asm 4.593 lines
// ============================================
// output - Disassembled Source
// ============================================
// KickAssembler syntax
// Generated by Restore 64 v0.2.1 alpha build 298, 2026-04-11 21:36:46
// https://restore64.dev by datucker / Rabenauge
//
// Load address: $0800  End: $ffff  (63488 bytes)
// Crunched with Exomizer v2/v3 (with relocation) — depacked by emulation
// Packer entry: $0810 (via BASIC SYS 2064)
// Entry point:  $3200 (12800)
// IRQ handler:  $1030 (irq_1030)
//
// Code: 5136 bytes, Data: 58352 bytes
// Labels: 522, Subroutines: 31
//
// Cross-references: all OK
// ============================================


// --- Region $0810-$08c9 ---
.pc = $0810 "sub_0810"
// Referenced by: jsr from $326a, $ff81

sub_0810:
        ldx #$00

loc_0812:
.label sub_0813 = * + 1
.label sub_0814 = * + 2
        lda $d012
        cmp #$70
        bne loc_0812
        dex
        bne loc_0812
        rts
        brk

dat_081e:
        .byte $00,$00                               // ..
// Referenced by: jsr from $08a4, $1338, $e827, $ecf1

sub_0820:
        lda #$00
        sta smc_1334                                // SMC: modifies $1334
        lda #$16
        sta smc_1335                                // SMC: modifies $1335
        rts

dat_082b:
        .byte $00,$00,$00,$00,$00                   // .....
// Referenced by: jsr from $3201

sub_0830:
        jsr $ff5b
        lda #$00
        tax

loc_0836:
        sta $0120,x
        inx
        cpx #$80
        bne loc_0836
        lda #$7f
        sta $d01c
        lda #$01
        sta $d02e
        lda #$00
        sta $d028
        sta $d029
        sta $d02a
        sta $d02b
        sta $d02c
        sta $d02d
        lda #$0b
        sta $d026
        lda #$0c
        sta $d025
        lda #$0f
        sta $d027
        lda #$60
        sta $d000
        lda #$40
        sta $d001
        lda $d010
        ora #$01
        sta $d010
        lda #$00
        sta $10
        sta $11
        sta $05
        sta $02
        sta $08
        sta smc_1201                                // SMC: modifies $1201
        lda #$29
        sta $07f8
        sta $1289
        lda #$6a
        sta smc_3286                                // SMC: modifies $3286
        lda #$02
        sta $06
        sta $07
        sta $08
        jsr sub_08e0
        jsr sub_0820
        jsr sub_08eb
        lda #$37
        sta $07f9
        sta $07fa
        sta $07fb
        sta $07fc
        sta $07fd
        lda #$1f
        sta smc_135d                                // SMC: modifies $135d
        sta $1834
        jsr sub_0e00
        jsr sub_1000
        rts

// --- Region $08e0-$08f6 ---
.pc = $08e0 "sub_08e0"
// Referenced by: jsr from $08a1, $1255, $e824, $ec0e

sub_08e0:
        lda #$00
        sta $1251
        lda #$14
        sta $1252
        rts
// Referenced by: jsr from $08a7, $132a, $e82a, $ece3

sub_08eb:
        ldx #$00
        txa

loc_08ee:
        sta $0340,x
        inx
        cpx #$38
        bne loc_08ee
        rts

// --- Region $0e00-$0e1a ---
.pc = $0e00 "sub_0e00"
// Referenced by: jsr from $08c3, $e846

sub_0e00:
        ldx #$00

loc_0e02: