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open-roms/src/basic/memory/under_rom_60k.s
T

117 lines
2.2 KiB
ArmAsm

// #LAYOUT# STD * #TAKE
// #LAYOUT# * BASIC_0 #TAKE
// #LAYOUT# * * #IGNORE
#if CONFIG_MEMORY_MODEL_60K
// IMPORTANT:
// These routines lengths cannot be changed without changing
// the aliases for peek_under_roms, poke_under_roms, etc.
// Thus those addresses are expressed using formulae.
install_ram_routines:
// Copy routines into place
ldx #__ram_routines_end-__ram_routines_start-1
!:
lda __ram_routines_start,x
sta tiny_nmi_handler,x
dex
bpl !-
// Point NMI handler to tiny_nmi_handler
lda #<tiny_nmi_handler
sta $FFFE
lda #>tiny_nmi_handler
sta $FFFF
rts
__ram_routines_start:
// XXX - Routine order must match that of the KERNAL version of the file.
// (since it has fewer routines)
tiny_nmi_handler_routine:
inc missed_nmi_flag
rti
peek_under_roms_routine:
php
// Offset of arg of lda ($00),y
stx peek_under_roms+pa-peek_under_roms_routine+1
jsr memmap_allram
pa: lda ($00),y
jsr memmap_normal
plp
rts
poke_under_roms_routine:
php
// Offset of arg of lda ($00),y
stx poke_under_roms+pb-poke_under_roms_routine+1
jsr memmap_allram
pb: sta ($00),y
jsr memmap_normal
plp
rts
memmap_normal_routine:
pha
lda #$37
sta $01
pla
rts
memmap_allram_routine:
sei
pha
lda #$04
sta $01
pla
rts
shift_mem_up_routine:
// Move memmove__size bytes from memmove__src to memmove__dst, where memmove__dst > memmove__src
//
// This means we have to copy from the back end down.
// This routine assumes the pointers are already pointed to the end of the areas, and that .Y is correctly initialized
php
jsr memmap_allram
!:
lda (memmove__src),y
sta (memmove__dst),y
dey
bne !-
dec memmove__src+1
dec memmove__dst+1
dec memmove__size+1
bne !-
plp
jmp memmap_normal
shift_mem_down_routine:
// Move memmove__size bytes from memmove__src to memmove__dst, where memmove__dst > memmove__src
//
// This means we have to copy from the back end down.
// This routine assumes the pointers are already pointed to the end of the areas, and that .Y is correctly initialized
php
jsr memmap_allram
!:
lda (memmove__src),y
sta (memmove__dst),y
iny
bne !-
inc memmove__src+1
inc memmove__dst+1
dec memmove__size+1
bne !-
plp
jmp memmap_normal
__ram_routines_end:
#endif