more BASIC cleanup
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@@ -1,164 +0,0 @@
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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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//
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// Tries to execute the statement, and all the subsequent ones
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//
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basic_execute_statement:
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// Check for RUN/STOP
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lda STKEY
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bpl_16 cmd_stop
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// Skip over any white spaces and colons (':')
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!:
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jsr fetch_character
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cmp #$20 // space, can be skipped
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beq !-
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cmp #$3A // colon, can be skipped
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beq !-
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// Check if end of the line
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cmp #$00
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beq basic_end_of_line
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// Not end of the line - we actually have something to execute
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// XXX continue rework from here
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pha
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jsr unconsume_character
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pla
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// The checks should be done in order of frequency, so that we are as
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// fast as possible.
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cmp #$7f
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bcc not_a_token
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// It is a token - consume this character
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jsr consume_character
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#if !HAS_OPCODES_65C02
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// Get the jump table entry for it, push it on the stack, and then RTS to start it.
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tax
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lda command_jumptable_hi - $80, x
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pha
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lda command_jumptable_lo - $80, x
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pha
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rts
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#else // HAS_OPCODES_65C02
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asl
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tax
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jmp (command_jumptable, x)
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#endif
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not_a_token:
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// Space, which we can also just ignore
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cmp #$20
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beq basic_skip_char
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// End of line?
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cmp #$00
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beq basic_end_of_line
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// :, i.e., statement separator, which we can simply ignore
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cmp #$3a
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beq basic_skip_char
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// If all else fails, it is a syntax error
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jmp do_SYNTAX_error
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basic_skip_char:
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jsr consume_character
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jmp basic_execute_statement
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basic_end_of_line:
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// If we reach the end are in direct mode, then
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// go back to reading input, else look for the
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// next line, and advance to that, or else
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// return to READY prompt because we have run out
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// of program.
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// XXX - If not in direct mode, then advance to next line, if there is
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// one.
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// Are we in direct mode
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lda CURLIN+1
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cmp #$ff
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bne basic_not_direct_mode
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// Yes, we were in direct mode, so stop now
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jmp basic_main_loop
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basic_not_direct_mode:
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// Copy line number to previous line number
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lda CURLIN+0
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sta OLDLIN+0
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lda CURLIN+1
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sta OLDLIN+1
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// Advance the basic line pointer to the next line
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jsr basic_follow_link_to_next_line
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// Are we at the end of the program?
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lda OLDTXT+0
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ora OLDTXT+1
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bne basic_execute_from_current_line
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// End of program found
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jmp basic_main_loop
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basic_execute_from_current_line:
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// Check if pointer is null, if so, we are at the end of
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// the program.
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ldy #0
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jsr peek_line_pointer_null_check
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bcs !+
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// End of program reached
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jmp basic_main_loop
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!:
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// Skip pointer and line number to get address of first statement
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lda OLDTXT+0
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clc
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adc #4
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sta TXTPTR+0
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lda OLDTXT+1
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adc #0
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sta TXTPTR+1
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ldy #2
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#if CONFIG_MEMORY_MODEL_60K
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ldx #<OLDTXT
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jsr peek_under_roms
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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 CURLIN+0
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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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#else // CONFIG_MEMORY_MODEL_38K
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lda (OLDTXT),y
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#endif
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sta CURLIN+1
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jmp basic_execute_statement
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@@ -5,10 +5,6 @@
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basic_main_loop:
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// XXX - Check if direct or program mode, and get next line of input
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// the appropriate way.
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// XXX - For now, it is hard coded to direct mode
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// Tell user we are ready
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jsr ready_message
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@@ -177,4 +173,4 @@ not_a_line:
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lda #$FF
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sta CURLIN+1
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jmp basic_execute_statement
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jmp execute_statements
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@@ -7,6 +7,6 @@ cmd_clr:
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jsr basic_do_clr
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// CLR command does not stop execution
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// (Cconfirmed on a c64)
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jmp basic_execute_statement
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// CLR command does not stop execution (confirmed on a C64)
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jmp execute_statements
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@@ -65,7 +65,7 @@ cmd_load_no_error:
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// For VERIFY - this is it
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lda VERCKB
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bne_16 basic_execute_statement
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bne_16 execute_statements
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// C64 BASIC apparently does not clear variables after a LOAD in the
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// middle of a program. For safety, we do.
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@@ -89,7 +89,7 @@ cmd_load_no_error:
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inx
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beq cmd_load_end // branch if direct mode
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jmp basic_execute_from_current_line
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jmp execute_line
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cmd_load_end:
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@@ -7,6 +7,6 @@ cmd_new:
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jsr basic_do_new
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// NEW command terminates execution
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// (Confirmed on a C64)
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// NEW command terminates execution (confirmed on a C64)
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jmp basic_main_loop
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@@ -85,4 +85,4 @@ cmd_print_new_line_done:
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cmd_print_done:
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jmp basic_execute_statement
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jmp execute_statements
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@@ -6,4 +6,5 @@
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// REM statement just skips to the next line
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cmd_rem:
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jmp basic_end_of_line
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jmp execute_statements_end_of_line
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@@ -24,4 +24,4 @@ cmd_goto:
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jmp do_UNDEFD_STATEMENT_error
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!:
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// Run it!
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jmp basic_execute_from_current_line
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jmp execute_line
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@@ -36,4 +36,4 @@ cmd_save:
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// The end
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jmp basic_execute_statement
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jmp execute_statements
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@@ -62,7 +62,7 @@ cmd_sys_setup_call:
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// Call the routine.
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jsr USRPOK
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jmp basic_execute_statement
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jmp execute_statements
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//
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@@ -7,6 +7,9 @@
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//
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// XXX use separate jumptables for commands and functions
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.const command_list = List().add(
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// $80 - $8F
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@@ -0,0 +1,124 @@
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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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//
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// Tries to execute the statement, and all the subsequent ones
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//
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execute_statements:
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// Check for RUN/STOP
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lda STKEY
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bpl_16 cmd_stop
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// Skip over any white spaces and colons (':')
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!:
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jsr fetch_character
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cmp #$20 // space, can be skipped
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beq !-
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cmp #$3A // colon, can be skipped
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beq !-
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// Check if end of the line
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cmp #$00
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beq execute_statements_end_of_line
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// Not end of the line - it seems we actually have something to execute
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cmp #$7F
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bcc_16 do_SYNTAX_error // branch if not a token XXX here we should handle variable assignments
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#if !HAS_OPCODES_65C02
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// Get the jump table entry for it, push it on the stack, and then RTS to start it.
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tax
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lda command_jumptable_hi - $80, x
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pha
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lda command_jumptable_lo - $80, x
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pha
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rts
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#else // HAS_OPCODES_65C02
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// Use jumptable to go to the token
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asl
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tax
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jmp (command_jumptable, x)
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#endif
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execute_statements_end_of_line:
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// First check, if we are in direct mode - if so,
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// end the execution and go to main loop
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ldx CURLIN+1
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inx
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beq_16 basic_main_loop
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// Advance to the next line - first copy the line number
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// to previous line number
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lda CURLIN+0
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sta OLDLIN+0
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lda CURLIN+1
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sta OLDLIN+1
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// Advance the basic line pointer to the next line; if end,
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// go to the main loop
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jsr basic_follow_link_to_next_line
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lda OLDTXT+0
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ora OLDTXT+1
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beq_16 basic_main_loop
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// FALLTROUGH
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execute_line:
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// Check if pointer is null, if so, we are at the end of the program
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ldy #0
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jsr peek_line_pointer_null_check
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bcc_16 basic_main_loop // branch if end of program reached
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// Skip pointer and line number to get address of first statement
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lda OLDTXT+0
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clc
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adc #$04
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sta TXTPTR+0
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lda OLDTXT+1
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adc #$00
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sta TXTPTR+1
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ldy #$02
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#if CONFIG_MEMORY_MODEL_60K
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ldx #<OLDTXT
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jsr peek_under_roms
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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 CURLIN+0
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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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#else // CONFIG_MEMORY_MODEL_38K
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lda (OLDTXT),y
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#endif
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sta CURLIN+1
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jmp execute_statements
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File renamed without changes.
@@ -98,7 +98,7 @@ wedge_dos_change_drive:
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!:
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sta FA
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jsr print_return
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jmp basic_end_of_line
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jmp basic_main_loop
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wedge_dos_status_get:
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