Files
open-roms/c64/basic/basic_shift_mem_up.s
T

209 lines
4.1 KiB
ArmAsm

#if ROM_LAYOUT_STD || (ROM_LAYOUT_M65 && SEGMENT_BASIC_0)
basic_shift_mem_up_and_relink:
// Shift memory up from OLDTXT
// X bytes.
// NOTE: Pointers need to be reduced by one, due to the way
// the copyroutine works, so we do that here.
// Work out end point of destination
txa
clc
adc VARTAB+0
sta __memmove_dst+0
lda VARTAB+1
adc #0
sta __memmove_dst+1
lda __memmove_dst+0
sec
sbc #1
sta __memmove_dst+0
lda __memmove_dst+1
sbc #0
sta __memmove_dst+1
// End point of source is just current end of BASIC text
lda VARTAB+0
sec
sbc #1
sta __memmove_src+0
lda VARTAB+1
sbc #0
sta __memmove_src+1
// Work out size of region to copy
lda VARTAB+0
sec
sbc OLDTXT+0
sta __memmove_size+0
lda VARTAB+1
sbc OLDTXT+1
sta __memmove_size+1
// jsr printf
// .text "TOP OF BASIC = $"
// .byte $f1,<VARTAB,>VARTAB
// .byte $f0,<VARTAB,>VARTAB
// .byte $0d
// .text "SHIFTING UP $"
// .byte $f1,<__memmove_size,>__memmove_size
// .byte $f0,<__memmove_size,>__memmove_size
// .text " BYTES FROM $"
// .byte $f1,<__memmove_src,>__memmove_src
// .byte $f0,<__memmove_src,>__memmove_src
// .text " TO $"
// .byte $f1,<__memmove_dst,>__memmove_dst
// .byte $f0,<__memmove_dst,>__memmove_dst
// .byte $0d,0
// To make life simple for the copy routine that lives in RAM,
// we have to adjust the end pointers down one page and set Y to the low
// byte of the copy size.
lda __memmove_src+0
sec
sbc __memmove_size+0
sta __memmove_src+0
lda __memmove_src+1
sbc #0
sta __memmove_src+1
lda __memmove_dst+0
sec
sbc __memmove_size+0
sta __memmove_dst+0
lda __memmove_dst+1
sbc #0
sta __memmove_dst+1
// Now make exit easy, by being able to check for zero on size high byte when done
inc __memmove_size+1
// Then set Y to the number offset required
ldy __memmove_size+0
iny
stx __tokenise_work3
// jsr printf
// .text "REVISED BOUNDS $"
// .byte $f1,<__memmove_size,>__memmove_size
// .byte $f0,<__memmove_size,>__memmove_size
// .text " BYTES FROM $"
// .byte $f1,<__memmove_src,>__memmove_src
// .byte $f0,<__memmove_src,>__memmove_src
// .text " TO $"
// .byte $f1,<__memmove_dst,>__memmove_dst
// .byte $f0,<__memmove_dst,>__memmove_dst
// .byte $0d,0
// Do the copy
jsr shift_mem_up
// Now fix the pointer to the next line
// First, we need to point the current BASIC line
// pointer to itself, so that we can add the shift
// to make it end up pointing to the next line
ldy #0
lda OLDTXT+0
#if CONFIG_MEMORY_MODEL_60K
ldx #<OLDTXT+0
jsr poke_under_roms
#else // CONFIG_MEMORY_MODEL_38K
sta (OLDTXT),y
#endif
iny
lda OLDTXT+1
#if CONFIG_MEMORY_MODEL_60K
jsr poke_under_roms
#else // CONFIG_MEMORY_MODEL_38K
sta (OLDTXT),y
#endif
relink_up_next_line:
// inc $d020
// jmp relink_up_next_line
// Advance pointer by tokenise_word3 bytes
ldy #0
#if CONFIG_MEMORY_MODEL_60K
ldx #<OLDTXT+0
jsr peek_under_roms
#else // CONFIG_MEMORY_MODEL_38K
lda (OLDTXT),y
#endif
sta __memmove_dst+0
clc
adc __tokenise_work3
sta __memmove_src+0
iny
php
#if CONFIG_MEMORY_MODEL_60K
jsr peek_under_roms
cmp #$00
#else // CONFIG_MEMORY_MODEL_38K
lda (OLDTXT),y
#endif
sta __memmove_dst+1
plp
adc #0
sta __memmove_src+1
// jsr printf
// .text "LINE ADDR = $"
// .byte $f1,<OLDTXT,>VARTAB
// .byte $f0,<OLDTXT,>VARTAB
// .text $d," BEFORE = $"
// .byte $f1,<__memmove_dst,>__memmove_dst
// .byte $f0,<__memmove_dst,>__memmove_dst
// .text ", AFTER = $"
// .byte $f1,<__memmove_src,>__memmove_src
// .byte $f0,<__memmove_src,>__memmove_src
// .byte $d
// .byte 0
// Write __memmove_src back to current line pointer
ldy #0
lda __memmove_src+0
#if CONFIG_MEMORY_MODEL_60K
ldx #<OLDTXT+0
jsr poke_under_roms
#else // CONFIG_MEMORY_MODEL_38K
sta (OLDTXT),y
#endif
iny
lda __memmove_src+1
#if CONFIG_MEMORY_MODEL_60K
jsr poke_under_roms
#else // CONFIG_MEMORY_MODEL_38K
sta (OLDTXT),y
#endif
relink_up_loop:
// Now advance pointer to the next line,
lda __memmove_src+0
sta OLDTXT+0
lda __memmove_src+1
sta OLDTXT+1
// Have we run out of lines to patch?
jsr peek_line_pointer_null_check
bcs relink_up_next_line
rts
#endif // ROM layout