CODE ASM SOUS RASM ; first we need to define some constant in order to use RMR and RMR2 ; RMR tags MODE_0 equ 0 MODE_1 equ 1 MODE_2 equ 2 MODE_3 equ 3 ROM_OFF equ %1100 ROM_BOTH equ 0 ROM_UP equ %100 ROM_LOW equ %1000 INTRESET equ %10000 macro RMR tags ld bc,#7F80+{tags} out (c),c mend ; RMR2 tags ROM0 equ 0 ROM1 equ 1 ROM2 equ 2 ROM3 equ 3 ROM4 equ 4 ROM5 equ 5 ROM6 equ 6 ROM7 equ 7 ASICOFF equ 0 ROM0000 equ 0 ROM4000 equ %01000 ROM8000 equ %10000 ASICON equ %11000 macro RMR2 tags ld bc,#7FA0+{tags} out (c),c mend ; init cartridge output mode buildcpr ; write in the very first ROM, which will be mapped simultaneously in #0000 and #C000 at boot bank 0 here_we_go ; interrupt should be disabled but this allow the code to be used as software reset di ; unlike Winape, at boot, a real Amstrad Plus is not in IM 1 im 1 RMR ROM_LOW|MODE_2 ; disable upper ROM, in case of software reset ; reset RAM mapping in case of software reset, again... ld bc,#7FC0 out (c),c ; reset RAM ld hl,#0000 ld bc,4 .reset_ram repeat 32 : push hl : rend : djnz .reset_ram : dec c : jr nz,.reset_ram ; preset PPI ld bc,#F782 : out (c),c ld b,#F4 : out (c),0 ld b,#F6 : out (c),0 ; setup a screen (not the one when prompt Basic on CPC...) ld bc,#BC00 : out (c),c : ld bc,#BD00+63 : out (c),c ld bc,#BC01 : out (c),c : ld bc,#BD00+10 : out (c),c ld bc,#BC02 : out (c),c : ld bc,#BD00+42 : out (c),c ld bc,#BC03 : out (c),c : ld bc,#BD8E : out (c),c ld bc,#BC04 : out (c),c : ld bc,#BD00+38 : out (c),c ld bc,#BC06 : out (c),c : ld bc,#BD00+00 : out (c),c ld bc,#BC07 : out (c),c : ld bc,#BD00+34 : out (c),c ld bc,#BC09 : out (c),c : ld bc,#BD00+7 : out (c),c ld bc,#BC0C : out (c),c : ld bc,#BD30 : out (c),c ld bc,#BC0D : out (c),c : ld bc,#BD00 : out (c),c ; unlock asic ld bc,#bc11 ld hl,asic_unlock_sequence .unlock_asic inc b outi dec c jr nz,.unlock_asic RMR2 ASICON|ROM0 ; reset ASIC registers, in case of software reset... ld sp,#8000 ld hl,#0000 ld b,l .reset_asic repeat 32 : push hl : rend : djnz .reset_asic ;******************************************************************** ; now we are in an almost proper state ;******************************************************************** ld hl,0 ld de,0 ld bc,16384 ldir RMR ROM_OFF ld hl,#C9FB : ld (#38),hl ld hl,#6800 : ld (hl),1 ei ld hl,#6421 reloop ld de,#000 ld b,254 halt : nop 5 nop 64-7 : dec hl : ld (hl),255 : inc hl rasta repeat 16 : inc (hl) : rend : dec hl : ld (hl),b : inc hl : nop 6 : djnz rasta : nop repeat 16 : inc (hl) : rend : dec hl : ld (hl),b : inc hl : nop 6 : nop 4 repeat 16 : inc (hl) : rend jp reloop asic_unlock_sequence defb #ff,#00,#ff,#77,#b3,#51,#a8,#d4,#62,#39,#9c,#46,#2b,#15,#8a,#cd,#ee