212 lines
3.5 KiB
ArmAsm
212 lines
3.5 KiB
ArmAsm
// #LAYOUT# STD * #TAKE
|
|
// #LAYOUT# * BASIC_0 #TAKE
|
|
// #LAYOUT# * * #IGNORE
|
|
|
|
|
|
fetch_variable:
|
|
|
|
// Fetch variable name
|
|
|
|
lda #$00
|
|
sta VARNAM+1
|
|
|
|
// Fetch the first character
|
|
!:
|
|
jsr fetch_character
|
|
cmp #$20 // ignore all the spaces
|
|
beq !-
|
|
|
|
jsr fetch_variable_is_AZ
|
|
bcs_16 do_SYNTAX_error
|
|
|
|
sta VARNAM+0
|
|
|
|
// Fetch the (optional) second character
|
|
|
|
jsr fetch_character
|
|
jsr fetch_variable_is_09_AZ
|
|
bcs fetch_variable_check_type
|
|
|
|
sta VARNAM+1
|
|
|
|
// Fetch the remaining variable characters - ignore them
|
|
!:
|
|
jsr fetch_character
|
|
jsr fetch_variable_is_09_AZ
|
|
bcc !-
|
|
|
|
// FALLTROUGH
|
|
|
|
fetch_variable_check_type:
|
|
|
|
// Encode variable type within name, as documented in:
|
|
// - https://sites.google.com/site/h2obsession/CBM/basic/variable-format
|
|
|
|
cmp #$24 // '$'
|
|
beq fetch_variable_type_string
|
|
cmp #$25 // '%'
|
|
beq fetch_variable_type_integer
|
|
|
|
// FALLTORUGH
|
|
|
|
fetch_variable_type_float:
|
|
|
|
jsr unconsume_character
|
|
|
|
#if HAS_OPCODES_65C02
|
|
bra fetch_variable_find_addr
|
|
#else
|
|
jmp fetch_variable_find_addr
|
|
#endif
|
|
|
|
fetch_variable_type_integer:
|
|
|
|
lda VARNAM+0
|
|
ora #$80
|
|
sta VARNAM+0
|
|
|
|
// FALLTROUGH
|
|
|
|
fetch_variable_type_string:
|
|
|
|
lda VARNAM+1
|
|
ora #$80
|
|
sta VARNAM+1
|
|
|
|
// FALLTROUGH
|
|
|
|
fetch_variable_find_addr:
|
|
|
|
// Now try to find variable address between VARTAB and ARYTAB, see
|
|
// - https://www.c64-wiki.com/wiki/Memory_(BASIC)
|
|
|
|
lda VARTAB+0
|
|
sta VARPNT+0
|
|
lda VARTAB+1
|
|
sta VARPNT+1
|
|
|
|
// FALLTROUGH
|
|
|
|
fetch_variable_find_addr_loop:
|
|
|
|
// Check if end of search loop
|
|
|
|
lda VARPNT+1
|
|
cmp ARYTAB+1
|
|
bne !+
|
|
lda VARPNT+0
|
|
cmp VARPNT+0
|
|
beq fetch_variable_alocate
|
|
!:
|
|
// Compare current variable name with searched one
|
|
// XXX consider creating optimized version for 46K/50K memory models
|
|
|
|
ldy #$00
|
|
|
|
#if CONFIG_MEMORY_MODEL_60K
|
|
ldx #<VARPNT
|
|
jsr peek_under_roms
|
|
#elif CONFIG_MEMORY_MODEL_46K || CONFIG_MEMORY_MODEL_50K
|
|
jsr peek_under_roms_via_VARPNT
|
|
#else // CONFIG_MEMORY_MODEL_38K
|
|
lda (VARPNT),y
|
|
#endif
|
|
|
|
cmp VARNAM+0
|
|
bne fetch_variable_find_addr_next
|
|
|
|
iny
|
|
|
|
#if CONFIG_MEMORY_MODEL_60K
|
|
jsr peek_under_roms
|
|
#elif CONFIG_MEMORY_MODEL_46K || CONFIG_MEMORY_MODEL_50K
|
|
jsr peek_under_roms_via_VARPNT
|
|
#else // CONFIG_MEMORY_MODEL_38K
|
|
lda (VARPNT),y
|
|
#endif
|
|
|
|
cmp VARNAM+1
|
|
bne fetch_variable_find_addr_next
|
|
|
|
// FALLTROUGH
|
|
|
|
fetch_variable_adjust_VARPNT:
|
|
|
|
// Adjust VARPNT to point just after variable name and quit
|
|
|
|
#if !HAS_OPCODES_65CE02
|
|
|
|
clc
|
|
lda VARPNT+0
|
|
adc #$02
|
|
sta VARPNT+0
|
|
bcc !+
|
|
inc VARPNT+1
|
|
!:
|
|
#else // HAS_OPCODES_65CE02
|
|
|
|
inw VARPNT
|
|
inw VARPNT
|
|
|
|
#endif
|
|
|
|
rts
|
|
|
|
fetch_variable_find_addr_next:
|
|
|
|
// Increase VARPNT by 7 - constant value, each variable uses 7 bytes, see:
|
|
// - https://sites.google.com/site/h2obsession/CBM/basic/variable-format
|
|
|
|
clc
|
|
lda VARPNT+0
|
|
adc #$07
|
|
sta VARPNT+0
|
|
bcc fetch_variable_find_addr_loop
|
|
inc VARPNT+1
|
|
bne fetch_variable_find_addr_loop // branch always
|
|
|
|
fetch_variable_alocate:
|
|
|
|
// First check if we have enough space for a new descriptor
|
|
|
|
// XXX
|
|
|
|
// If needed, move all the arrays up
|
|
|
|
// XXX
|
|
|
|
// Set pointer to new variable
|
|
|
|
// XXX
|
|
|
|
// Fill-in the new variable name, descriptor (it is enough to zero first 2 bytes of content)
|
|
|
|
ldy #$00
|
|
|
|
#if CONFIG_MEMORY_MODEL_60K
|
|
|
|
// XXX
|
|
|
|
#else // CONFIG_MEMORY_MODEL_38K || CONFIG_MEMORY_MODEL_46K || CONFIG_MEMORY_MODEL_50K
|
|
|
|
lda VARNAM+0
|
|
sta (VARPNT),y
|
|
iny
|
|
lda VARNAM+1
|
|
sta (VARPNT),y
|
|
iny
|
|
lda #$00
|
|
sta (VARPNT),y
|
|
iny
|
|
sta (VARPNT),y
|
|
|
|
#endif
|
|
|
|
// Adjust variable pointer and quit
|
|
|
|
#if HAS_OPCODES_65C02
|
|
bra fetch_variable_adjust_VARPNT
|
|
#else
|
|
jmp fetch_variable_adjust_VARPNT
|
|
#endif
|