some cleanup, BASIC line finding now properly uses stack
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FeralChild64 committed
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@@ -0,0 +1,105 @@
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// #LAYOUT# STD * #TAKE
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// #LAYOUT# * BASIC_0 #TAKE
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// #LAYOUT# * * #IGNORE
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// Find the BASIC line with number LINNUM
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// XXX it should be possible to start from the current line (OLDTXT), or from the startup,
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// depending on the current and target line number
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find_line:
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// Get pointer to start of BASIC text
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lda TXTTAB+0
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sta OLDTXT+0
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lda TXTTAB+1
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sta OLDTXT+1
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// FALLTROUGH
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find_line_loop:
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// Fetch the high byte of line number and compare
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ldy #$03
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#if CONFIG_MEMORY_MODEL_60K
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ldx #<OLDTXT+0
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jsr peek_under_roms
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#elif CONFIG_MEMORY_MODEL_46K || CONFIG_MEMORY_MODEL_50K
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jsr peek_under_roms_via_OLDTXT
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#else // CONFIG_MEMORY_MODEL_38K
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lda (OLDTXT),y
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#endif
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cmp LINNUM+1
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beq !+
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bcs find_line_fail // branch if line number too high
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bne find_line_next
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!:
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// Fetch the low byte of line number and compare
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dey
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#if CONFIG_MEMORY_MODEL_60K
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jsr peek_under_roms
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#elif CONFIG_MEMORY_MODEL_46K || CONFIG_MEMORY_MODEL_50K
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jsr peek_under_roms_via_OLDTXT
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#else // CONFIG_MEMORY_MODEL_38K
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lda (OLDTXT),y
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#endif
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cmp LINNUM+0
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beq find_line_success
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bcs find_line_fail // branch if line number too high
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bne find_line_next
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find_line_success:
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clc
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rts
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find_line_next:
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// Advance to the next line
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jsr peek_line_pointer_null_check
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bcc find_line_fail // branch in no more lines exist
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ldy #$00
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#if CONFIG_MEMORY_MODEL_60K
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ldx #<OLDTXT+0
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jsr peek_under_roms
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#elif CONFIG_MEMORY_MODEL_46K || CONFIG_MEMORY_MODEL_50K
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jsr peek_under_roms_via_OLDTXT
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#else // CONFIG_MEMORY_MODEL_38K
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lda (OLDTXT),y
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#endif
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pha
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iny
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#if CONFIG_MEMORY_MODEL_60K
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jsr peek_under_roms
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#elif CONFIG_MEMORY_MODEL_46K || CONFIG_MEMORY_MODEL_50K
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jsr peek_under_roms_via_OLDTXT
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#else // CONFIG_MEMORY_MODEL_38K
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lda (OLDTXT),y
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#endif
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sta OLDTXT+1
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pla
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sta OLDTXT+0
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#if HAS_OPCODES_65C02
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bra find_line_loop
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#else
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jmp find_line_loop
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#endif
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find_line_fail:
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sec
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rts
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@@ -0,0 +1,192 @@
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// #LAYOUT# STD * #TAKE
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// #LAYOUT# * BASIC_0 #TAKE
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// #LAYOUT# * * #IGNORE
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shell_main_loop:
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// Tell user we are ready
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ldx #IDX__STR_READY
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jsr print_packed_misc_str
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// Enable Kernal messages
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lda #$80
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jsr JSETMSG
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shell_read_next_line:
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// Read a line of input
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ldx #$00
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!:
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jsr JCHRIN
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bcs !-
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// Check for RETURN key
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cmp #$0D
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beq shell_got_line
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// Not carriage return, so try to append to line so far
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cpx #80
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bcs_16 do_STRING_TOO_LONG_error // see Computes Mapping the 64 p93
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sta BUF,x
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inx
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jmp !-
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shell_got_line:
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// Store length of input buffer ready for tokenising
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stx __tokenise_work1
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// XXX we should probably store 0 at the end of used BUF
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// FALLTROUGH
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shell_strip_leading_spaces:
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// Strip leading spaces from the line
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lda BUF
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cmp #$20
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bne shell_process_line // branch if no more leading spaces
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// We have a leading space - strip it away
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ldx #$01
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!:
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lda BUF,x
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sta BUF-1,x
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inx
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cpx __tokenise_work1
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bne !-
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// Reduce length of input by one
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dec __tokenise_work1
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// Stop trying to rim if we run out of input
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bne shell_strip_leading_spaces
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// FALLTROUGH
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shell_process_line:
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// Print a new line
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jsr print_return
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// Ignore empty lines
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lda __tokenise_work1
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beq shell_read_next_line
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// Check if a wedge should take over
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#if CONFIG_DOS_WEDGE || CONFIG_TAPE_WEDGE
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ldx __tokenise_work1 // size of the input, wedges need this XXX this should not be needed
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// Check if DOS wedge should take over
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lda BUF
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#if CONFIG_DOS_WEDGE
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cmp #$40 // '@'
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beq_16 wedge_dos
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#endif
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#if CONFIG_TAPE_WEDGE
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cmp #$5F // left arrow
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beq_16 wedge_tape
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#endif
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#endif
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// Tokenise the line
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jsr tokenise_line
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// Has the user entered a line of BASIC beginning with a number?
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lda BUF
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cmp #$30
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bcc shell_execute_line
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cmp #$39
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bcs shell_execute_line
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// Yes, the line begins with a number - parse it and check validity
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// The injest_number follows __tokenise_work1 as the offset into the line,
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// so remember the line length somewhere else for now.
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lda __tokenise_work1
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sta __tokenise_work2
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lda #$00
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sta __tokenise_work1
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// Try to read line number
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lda #<BUF
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sta TXTPTR+0
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lda #>BUF
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sta TXTPTR+1
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jsr basic_parse_line_number
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// Get pointer to next char
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lda TXTPTR+0
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sta __tokenise_work1
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// Got a valid line number - we will be adding/deleting a new line
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// Skip any spaces after the line number
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ldx __tokenise_work1
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!:
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lda BUF,x
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cmp #$20
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bne !+
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inx
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bne !-
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!:
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stx __tokenise_work1
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// FALLTROUGH
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shell_add_delete_line:
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// First, clear all variables, so that we only have to shove BASIC text around
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jsr basic_do_clr
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.break
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// Delete line if present
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jsr find_line
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// XXX
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bcs !+
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// Delete the line, whether we are deleting or
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// replacing the line
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jsr basic_delete_line
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!:
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// Insert new line if non-zero length, i.e., that
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// we are not just deleting the line.
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lda __tokenise_work1
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cmp __tokenise_work2
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beq !+
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jsr basic_insert_line
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!:
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// No READY message after entering or deleting a line of BASIC
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jmp shell_read_next_line
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shell_execute_line:
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// Setup pointer to the statement
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lda #<BUF
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sta TXTPTR+0
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lda #>BUF
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sta TXTPTR+1
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// There is no stored line, so zero that pointer out
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lda #$00
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sta OLDTXT+0
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sta OLDTXT+1
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// Put invalid line number in current line number value,
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// so that we know we are in direct mode (Computes Mapping the 64 p19)
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lda #$FF
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sta CURLIN+1
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jmp execute_statements
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@@ -0,0 +1,37 @@
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// #LAYOUT# STD * #TAKE
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// #LAYOUT# M65 BASIC_1 #TAKE
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// #LAYOUT# X16 BASIC_0 #TAKE
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// #LAYOUT# * * #IGNORE
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//
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// Cuts away unnecessary characters after tokenizing a keyword
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//
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tk_cut_away_2: // for two-bytes tokenized keywords
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dec tk__len_unpacked
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// FALLTROUGH
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tk_cut_away_1: // for single-byte tokenized keywords
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dec tk__len_unpacked // keyword length, afterwards number of bytes to cut away
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inc tk__offset
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ldy tk__offset
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lda tk__len_unpacked
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clc
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adc tk__offset
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tax
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!:
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lda BUF, x
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sta BUF, y
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beq !+
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inx
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iny
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bne !-
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!:
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rts
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@@ -0,0 +1,229 @@
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// #LAYOUT# STD * #TAKE
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// #LAYOUT# M65 BASIC_1 #TAKE
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// #LAYOUT# X16 BASIC_0 #TAKE
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// #LAYOUT# * * #IGNORE
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//
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// Packs a keyword candidate using a simple compression scheme,
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// same as in 'generate_strings.cc'.
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//
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// This allows us to search through the compressed tokens directly
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// using the compressed fragment of BASIC, and thus work out the
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// token for a given piece of string.
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//
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// This also helps ensure that we have an implementation that is totally
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// different to that of the original C64 BASIC, as well as likely
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// saving a bit of space in the ROM, especially once we start implementing
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// larger keyword vocabs for extended BASIC, since the compression and
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// decompression machinery is of fixed size.
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//
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// Input:
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// - .X = offset of string to pack, address is BUF ($0200) + .X
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// Output:
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// - see labels in 'tk_pack'
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//
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tk_pack:
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// Reuse the CPU stack - addresses below $102 are used by 'tokenise_line.s'
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.label tk__len_unpacked = $103 // length of unpacked data; it could replace 'tk__nibble_flag', but at the cost of code size/performance
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.label tk__shorten_bits = $104 // 2 bytes for quick shortening of packed candidate
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.label tk__nibble_flag = $106 // $00 = start from new byte, $FF = start from high nibble
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.label tk__byte_offset = $107 // offset of the current byte (to place new data) in tk__packed
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.label tk__packed = $108 // packed candidate, 25 bytes is enough for worst case - a 16 byte keyword
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// Initialize variables
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lda #$00
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ldy #($04 + 25) // initialize 5 bytes of data + 25 bytes of space for packing
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!:
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sta tk__len_unpacked, y
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dey
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bpl !-
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// FALLTROUGH
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tk_pack_loop:
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// Get the next character
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lda BUF, x
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// If character cannot be a part of a keyword - do not pack anything more
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cmp #$23 // '#' - first sane character for a keyword
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bcc tk_pack_done // branch if below '#'
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cmp #$7B // 'Z' + 1
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bcs tk_pack_done // branch if above 'Z'
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// Keywords should not contain digits, colons, or semicolons
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cmp #$30
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bcc !+ // branch if below '0'
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cmp #$3C
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bcc tk_pack_done // branch if below '<'
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!:
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// Try to find a nibble to encode the character
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ldy #$0E
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!:
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cmp packed_as_1n-1, y
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beq tk_pack_1n
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dey
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bne !-
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// Try to find a 3-nibble sequence to encode the character (1st nibble is always 0xF in this case)
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ldy #TK__PACKED_AS_3N
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!:
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cmp packed_as_3n-1, y
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beq tk_pack_3n
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dey
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bne !-
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// If it is not on the list, it cannot be a part of token - quit
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// FALLTROUGH
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tk_pack_done:
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rts
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tk_pack_1n:
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// .Y contains our nibble; check whether we should start a new encoded byte
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bit tk__nibble_flag
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bpl tk_pack_1n_new_byte
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// Store in the high nibble of the current byte
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tya
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asl
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asl
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asl
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asl
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||||
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ldy tk__byte_offset
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ora tk__packed, y
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sta tk__packed, y
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// Adjust remaining counters / flags
|
||||
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inc tk__byte_offset
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inc tk__nibble_flag // $FF -> $00
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// FALLTROUGH
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tk_pack_1n_done:
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// Put the bit mark - to indicate 1-nibble encoding
|
||||
|
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clc
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ror tk__shorten_bits+0
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ror tk__shorten_bits+1
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||||
|
||||
// FALLTROUGH
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||||
|
||||
tk_pack_loop_next:
|
||||
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// Prepare for the next loop iteration - increment counters
|
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inx
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inc tk__len_unpacked
|
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// Check length, if it is OK to pack one more byte; quit if not
|
||||
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lda tk__len_unpacked
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cmp #TK__MAX_KEYWORD_LEN
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bne tk_pack_loop
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||||
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rts
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||||
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||||
tk_pack_1n_new_byte:
|
||||
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||||
// Store in the low nibble of the next byte
|
||||
|
||||
tya
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||||
ldy tk__byte_offset
|
||||
sta tk__packed, y
|
||||
|
||||
// Adjust remaining counters / flags
|
||||
|
||||
dec tk__nibble_flag // $00 -> $FF
|
||||
bmi tk_pack_1n_done
|
||||
|
||||
tk_pack_3n:
|
||||
|
||||
// .Y contains 2 nibbles to encode; check whether we should start a new encoded byte
|
||||
|
||||
bit tk__nibble_flag
|
||||
bpl tk_pack_3n_new_byte
|
||||
|
||||
// Store 1st nibble (alwys 0xF) in the high nibble of the current byte
|
||||
|
||||
phy_trash_a
|
||||
|
||||
lda #$F0
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||||
ldy tk__byte_offset
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||||
ora tk__packed, y
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sta tk__packed, y
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||||
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||||
// Store byte in the next byte
|
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iny
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pla
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sta tk__packed, y
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// Adjust remaining counters / flags
|
||||
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||||
iny
|
||||
sty tk__byte_offset
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inc tk__nibble_flag // $FF -> $00
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||||
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||||
// FALLTROUGH
|
||||
|
||||
tk_pack_3n_done:
|
||||
|
||||
// Put the bit mark - to indicate 3-nibble encoding
|
||||
|
||||
sec
|
||||
ror tk__shorten_bits+0
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||||
ror tk__shorten_bits+1
|
||||
|
||||
bcc tk_pack_loop_next // branch always
|
||||
|
||||
tk_pack_3n_new_byte:
|
||||
|
||||
// First store everything in the current byte, we will set '0xF' mark later
|
||||
|
||||
tya
|
||||
ldy tk__byte_offset
|
||||
sta tk__packed, y
|
||||
|
||||
// Now store just the low nibble in the next byte
|
||||
|
||||
iny
|
||||
and #$0F
|
||||
sta tk__packed, y
|
||||
|
||||
// Go back for a moment and set the '0xF' mark in the low nibble
|
||||
|
||||
dey
|
||||
lda tk__packed, y
|
||||
ora #$0F
|
||||
sta tk__packed, y
|
||||
iny
|
||||
|
||||
// Adjust remaining counters / flags
|
||||
|
||||
sty tk__byte_offset
|
||||
dec tk__nibble_flag // $00 -> $FF
|
||||
|
||||
bmi tk_pack_3n_done // branch always
|
||||
@@ -0,0 +1,93 @@
|
||||
// #LAYOUT# STD * #TAKE
|
||||
// #LAYOUT# M65 BASIC_1 #TAKE
|
||||
// #LAYOUT# X16 BASIC_0 #TAKE
|
||||
// #LAYOUT# * * #IGNORE
|
||||
|
||||
//
|
||||
// Search for a token on the list pointed by FRESPC
|
||||
//
|
||||
// Input:
|
||||
// - list address in FRESPC, has to be refreshed after routine call
|
||||
// - uses same variables as 'tk_pack'
|
||||
// Output:
|
||||
// - Carry set = not found
|
||||
// - .X = index of token found
|
||||
//
|
||||
|
||||
|
||||
tk_search:
|
||||
|
||||
ldx #$00 // initial token index
|
||||
|
||||
// FALLTROUGH
|
||||
|
||||
tk_search_loop:
|
||||
|
||||
// Check if end of the list
|
||||
|
||||
ldy #$00
|
||||
lda (FRESPC), y
|
||||
cmp #$FF
|
||||
bne tk_search_compare
|
||||
iny
|
||||
lda (FRESPC), y
|
||||
dey
|
||||
cmp #$FF
|
||||
bne tk_search_compare
|
||||
|
||||
// End of the list
|
||||
|
||||
sec
|
||||
rts
|
||||
|
||||
tk_search_compare:
|
||||
|
||||
// Compare the packed candidate with the current keyword list entry
|
||||
|
||||
lda (FRESPC), y
|
||||
cmp tk__packed, y
|
||||
bne tk_search_not_matching
|
||||
|
||||
cmp #$00
|
||||
beq tk_search_found
|
||||
|
||||
// For now everything matches, try the next byte
|
||||
|
||||
iny
|
||||
bne tk_search_compare // branch always
|
||||
|
||||
tk_search_not_matching:
|
||||
|
||||
inx // increment token index
|
||||
|
||||
// We need to find the end of the keyword on the list
|
||||
// and proceed one byte further
|
||||
|
||||
cmp #$00
|
||||
beq tk_search_next
|
||||
!:
|
||||
iny
|
||||
lda (FRESPC), y
|
||||
bne !-
|
||||
|
||||
// FALLTROUGH
|
||||
|
||||
tk_search_next:
|
||||
|
||||
// Update FRESPC - advance by .Y
|
||||
|
||||
iny
|
||||
tya
|
||||
clc
|
||||
adc FRESPC+0
|
||||
sta FRESPC+0
|
||||
lda FRESPC+1
|
||||
adc #$00
|
||||
sta FRESPC+1
|
||||
|
||||
bcc tk_search_loop // branch always
|
||||
|
||||
tk_search_found:
|
||||
|
||||
clc
|
||||
rts
|
||||
@@ -0,0 +1,113 @@
|
||||
// #LAYOUT# STD * #TAKE
|
||||
// #LAYOUT# M65 BASIC_1 #TAKE
|
||||
// #LAYOUT# X16 BASIC_0 #TAKE
|
||||
// #LAYOUT# * * #IGNORE
|
||||
|
||||
//
|
||||
// Shortens a keyword candidate previously packed by tk_pack by 1 character
|
||||
//
|
||||
// Input:
|
||||
// - uses same variables as 'tk_pack'
|
||||
//
|
||||
|
||||
|
||||
tk_shorten:
|
||||
|
||||
// First make sure we actually can shorten anything
|
||||
|
||||
dec tk__len_unpacked
|
||||
beq tk_shorten_end
|
||||
|
||||
// Now check if the last character was encoded as 1 nibble or 3 nibbles
|
||||
|
||||
asl tk__shorten_bits+1
|
||||
rol tk__shorten_bits+0
|
||||
bcs tk_shorten_3n
|
||||
|
||||
// FALLTROUGH
|
||||
|
||||
tk_shorten_1n:
|
||||
|
||||
ldy tk__byte_offset // will be needed in both cases
|
||||
|
||||
// Now we need to check which nibble to cut away
|
||||
|
||||
bit tk__nibble_flag
|
||||
bcs tk_shorten_1n_lo
|
||||
|
||||
// FALLTROUGH
|
||||
|
||||
tk_shorten_1n_hi: // tk__nibble_flag = $00, both nibbles free
|
||||
|
||||
// Go back one byte and clear the high nibble only
|
||||
|
||||
dey
|
||||
sty tk__byte_offset
|
||||
|
||||
lda tk__packed, y
|
||||
and #$F0
|
||||
sta tk__packed, y
|
||||
|
||||
// Adjust remaining counters / flags, and quit
|
||||
|
||||
dec tk__nibble_flag // $00 -> $FF
|
||||
|
||||
// FALLTROUGH
|
||||
|
||||
tk_shorten_end:
|
||||
|
||||
rts
|
||||
|
||||
tk_shorten_1n_lo: // tk__nibble_flag = $FF, only the high nibble is free
|
||||
|
||||
// Clear the whole byte, it will be faster
|
||||
|
||||
lda #$00
|
||||
sta tk__packed, y
|
||||
|
||||
// Adjust remaining counters / flags, and quit
|
||||
|
||||
inc tk__nibble_flag // $FF -> $00
|
||||
rts
|
||||
|
||||
tk_shorten_3n:
|
||||
|
||||
ldy tk__byte_offset // will be needed in both cases
|
||||
lda #$00
|
||||
|
||||
// Now we need to check which nibble to cut away
|
||||
|
||||
bit tk__nibble_flag
|
||||
bcs tk_shorten_3n_2bytes
|
||||
|
||||
// FALLTROUGH
|
||||
|
||||
tk_shorten_3n_byte_nibble: // tk__nibble_flag = $00, both nibbles free
|
||||
|
||||
// Go back one byte, clear it, go back and clear the high nibble only
|
||||
|
||||
dey
|
||||
sta tk__packed, y
|
||||
|
||||
// Reuse 'tk_shorten_1n_hi'
|
||||
|
||||
sty tk__byte_offset
|
||||
#if HAS_OPCODES_65C02
|
||||
bra tk_shorten_1n_hi
|
||||
#else
|
||||
jmp tk_shorten_1n_hi
|
||||
#endif
|
||||
|
||||
tk_shorten_3n_2bytes: // tk__nibble_flag = $FF, only the high nibble is free
|
||||
|
||||
// Clear the byte, go back, clear one more byte
|
||||
|
||||
sta tk__packed, y
|
||||
dey
|
||||
sta tk__packed, y
|
||||
|
||||
// Adjust remaining counters / flags, and quit
|
||||
|
||||
sty tk__byte_offset
|
||||
inc tk__nibble_flag // $FF -> $00
|
||||
rts
|
||||
@@ -0,0 +1,213 @@
|
||||
// #LAYOUT# STD * #TAKE
|
||||
// #LAYOUT# M65 * #TAKE
|
||||
// #LAYOUT# X16 BASIC_0 #TAKE
|
||||
// #LAYOUT# * * #IGNORE
|
||||
|
||||
//
|
||||
// Tokenise a line of BASIC stored at $0200
|
||||
//
|
||||
// Input:
|
||||
// - length in __tokenise_work1
|
||||
//
|
||||
|
||||
|
||||
tokenise_line:
|
||||
|
||||
#if (ROM_LAYOUT_M65 && SEGMENT_BASIC_0)
|
||||
|
||||
jsr map_BASIC_1
|
||||
jsr_ind VB1__tokenise_line
|
||||
jmp map_NORMAL
|
||||
|
||||
#else
|
||||
|
||||
// Reuse the CPU stack - addresses above $101 are used by 'tk_pack.s'
|
||||
|
||||
.label tk__offset = $100 // offset into string
|
||||
.label tk__length = $101 // length of the raw string XXX reuse __tokenise_work1?
|
||||
|
||||
// Initialize variables
|
||||
|
||||
lda #$00
|
||||
sta tk__offset
|
||||
|
||||
ldx __tokenise_work1
|
||||
stx tk__length
|
||||
|
||||
// Terminate input string with $00
|
||||
|
||||
// XXX do we need this?
|
||||
sta BUF, x
|
||||
|
||||
// FALLTROUGH
|
||||
|
||||
tokenise_line_loop:
|
||||
|
||||
// Check if we have reached end of the line
|
||||
|
||||
lda tk__offset
|
||||
cmp tk__length
|
||||
beq tokenise_line_done
|
||||
|
||||
// Check for some special characters
|
||||
|
||||
ldx tk__offset
|
||||
lda BUF, x
|
||||
|
||||
cmp #$22
|
||||
beq tokenise_line_quote
|
||||
|
||||
cmp #$DE
|
||||
beq tokenise_line_pi
|
||||
|
||||
cmp #$3F
|
||||
beq tokenise_line_question_mark // shortcut for PRINT command
|
||||
|
||||
// Try to tokenise
|
||||
|
||||
jsr tk_pack
|
||||
!:
|
||||
lda tk__len_unpacked
|
||||
beq tokenise_line_char // branch if attempt to tokenise failed
|
||||
|
||||
// Check for BASIC V2 tokens
|
||||
|
||||
lda #<packed_freq_keywords_V2
|
||||
sta FRESPC+0
|
||||
lda #>packed_freq_keywords_V2
|
||||
sta FRESPC+1
|
||||
|
||||
jsr tk_search
|
||||
bcc tokenise_line_keyword_V2 // branch if keyword identified
|
||||
|
||||
// Check for extended tokens
|
||||
|
||||
lda #<packed_freq_keywords_CC
|
||||
sta FRESPC+0
|
||||
lda #>packed_freq_keywords_CC
|
||||
sta FRESPC+1
|
||||
|
||||
jsr tk_search
|
||||
bcc tokenise_line_keyword_CC // branch if keyword identified
|
||||
|
||||
lda #<packed_freq_keywords_CD
|
||||
sta FRESPC+0
|
||||
lda #>packed_freq_keywords_CD
|
||||
sta FRESPC+1
|
||||
|
||||
jsr tk_search
|
||||
bcc tokenise_line_keyword_CD // branch if keyword identified
|
||||
|
||||
// Shorten packed keyword candidate and try again
|
||||
|
||||
jsr tk_shorten
|
||||
|
||||
#if HAS_OPCODES_65C02
|
||||
bra !-
|
||||
#else
|
||||
jmp !-
|
||||
#endif
|
||||
|
||||
tokenise_line_keyword_V2:
|
||||
|
||||
// .X contains a token ID, starting from 0
|
||||
|
||||
txa
|
||||
pha // store the token on the stack, we will need it for REM support
|
||||
|
||||
// Store the token
|
||||
|
||||
ldx tk__offset
|
||||
clc
|
||||
adc #$80
|
||||
sta BUF, x
|
||||
|
||||
// Cut away unnecessary bytes
|
||||
|
||||
jsr tk_cut_away_1
|
||||
|
||||
// Special handling for REM command - after this one nothing more should be tokenised
|
||||
|
||||
pla
|
||||
cmp #$0F // REM token index
|
||||
jmp tokenise_line_loop
|
||||
|
||||
// FALLTROUGH
|
||||
|
||||
tokenise_line_done:
|
||||
|
||||
// Update line length and quit
|
||||
|
||||
lda tk__length
|
||||
sta __tokenise_work1
|
||||
|
||||
rts
|
||||
|
||||
tokenise_line_quote:
|
||||
|
||||
// For the quote, we advance without tokenizing, until the next quote is found
|
||||
|
||||
inc tk__offset
|
||||
ldx tk__offset
|
||||
|
||||
lda BUF, x
|
||||
beq tokenise_line_done
|
||||
|
||||
cmp #$22
|
||||
beq tokenise_line_char
|
||||
bne tokenise_line_quote // branch always
|
||||
|
||||
tokenise_line_pi:
|
||||
|
||||
lda #$FF // token for PI
|
||||
skip_2_bytes_trash_nvz
|
||||
|
||||
// FALLTROUGH
|
||||
|
||||
tokenise_line_question_mark:
|
||||
|
||||
lda #$99 // token for PRINT
|
||||
sta BUF, x
|
||||
|
||||
// FALLTROUGH
|
||||
|
||||
tokenise_line_char:
|
||||
|
||||
inc tk__offset
|
||||
jmp tokenise_line_loop
|
||||
|
||||
|
||||
// Support for extended keyword lists
|
||||
|
||||
tokenise_line_keyword_CC:
|
||||
|
||||
// Store the token list index
|
||||
|
||||
lda #$CC
|
||||
skip_2_bytes_trash_nvz
|
||||
|
||||
// FALLTROUGH
|
||||
|
||||
tokenise_line_keyword_CD:
|
||||
|
||||
// Store the token list index
|
||||
|
||||
lda #$CD
|
||||
|
||||
ldy tk__offset
|
||||
sta BUF, y
|
||||
|
||||
// Store the sub-token itself
|
||||
|
||||
inx
|
||||
txa
|
||||
iny
|
||||
sty tk__offset
|
||||
sta BUF, y
|
||||
|
||||
// Cut away unnecessary bytes
|
||||
|
||||
jsr tk_cut_away_2
|
||||
jmp tokenise_line_loop
|
||||
|
||||
#endif // ROM layout
|
||||
Reference in new issue
Block a user