245 lines
4.1 KiB
ArmAsm
245 lines
4.1 KiB
ArmAsm
// #LAYOUT# STD * #TAKE
|
|
// #LAYOUT# * BASIC_0 #TAKE
|
|
// #LAYOUT# * * #IGNORE
|
|
|
|
//
|
|
// Tries to execute the statement, and all the subsequent ones
|
|
//
|
|
|
|
|
|
execute_statements:
|
|
|
|
// Check for RUN/STOP
|
|
|
|
lda STKEY
|
|
bpl_16 cmd_stop
|
|
|
|
// Skip over any white spaces and colons (':')
|
|
!:
|
|
jsr fetch_character
|
|
cmp #$20 // space, can be skipped
|
|
beq !-
|
|
cmp #$3A // colon, can be skipped
|
|
beq !-
|
|
|
|
// Check if end of the line
|
|
|
|
cmp #$00
|
|
beq execute_statements_end_of_line
|
|
|
|
// Not end of the line - it seems we actually have something to execute
|
|
|
|
// Initialize temporary string stack - just about any statement might need it
|
|
// XXX original C64 ROM initializes this during the startup too - not sure where to put this
|
|
|
|
ldx #$16
|
|
stx LASTPT
|
|
ldx #$19
|
|
stx TEMPPT
|
|
|
|
// Check if token is valid for execution
|
|
|
|
cmp #$7F
|
|
bcc_16 execute_statements_var_assign // not a token - try variable assign
|
|
|
|
cmp #$A6
|
|
bcs execute_statements_extended
|
|
|
|
#if !HAS_OPCODES_65C02
|
|
|
|
// Get the jump table entry for it, push it on the stack, and then RTS to start it.
|
|
|
|
tax
|
|
lda command_jumptable_hi - $80, x
|
|
pha
|
|
lda command_jumptable_lo - $80, x
|
|
pha
|
|
|
|
rts
|
|
|
|
#else // HAS_OPCODES_65C02
|
|
|
|
// Use jumptable to go to the command routine
|
|
|
|
asl
|
|
tax
|
|
jmp (command_jumptable, x)
|
|
|
|
#endif
|
|
|
|
|
|
execute_statements_extended:
|
|
|
|
// Support for extended BASIC commands
|
|
|
|
cmp #$CC
|
|
beq execute_statements_CC
|
|
cmp #$CD
|
|
beq execute_statements_CD
|
|
|
|
// 'GO' command has a strange token, it is placed after function tokens
|
|
|
|
cmp #$CB
|
|
beq_16 cmd_go
|
|
|
|
jmp do_SYNTAX_error
|
|
|
|
|
|
execute_statements_CC:
|
|
|
|
// Get the sub-token, check that it is valid
|
|
|
|
jsr fetch_character
|
|
cmp #$00
|
|
beq_16 do_SYNTAX_error
|
|
|
|
cmp #(TK__MAXTOKEN_keywords_CC+1)
|
|
bcs_16 do_SYNTAX_error
|
|
|
|
// Execute command
|
|
|
|
#if !HAS_OPCODES_65C02
|
|
|
|
// Get the jump table entry for it, push it on the stack, and then RTS to start it.
|
|
|
|
tax
|
|
lda command_CC_jumptable_hi - 1, x
|
|
pha
|
|
lda command_CC_jumptable_lo - 1, x
|
|
pha
|
|
|
|
rts
|
|
|
|
#else // HAS_OPCODES_65C02
|
|
|
|
// Use jumptable to go to the command routine
|
|
|
|
asl
|
|
tax
|
|
jmp (command_CC_jumptable - 2, x)
|
|
|
|
#endif
|
|
|
|
|
|
execute_statements_CD:
|
|
|
|
// Get the sub-token, check that it is valid
|
|
|
|
jsr fetch_character
|
|
cmp #$00
|
|
beq_16 do_SYNTAX_error
|
|
|
|
cmp #(TK__MAXTOKEN_keywords_CD+1)
|
|
bcs_16 do_SYNTAX_error
|
|
|
|
// Execute command
|
|
|
|
#if !HAS_OPCODES_65C02
|
|
|
|
// Get the jump table entry for it, push it on the stack, and then RTS to start it.
|
|
|
|
tax
|
|
lda command_CD_jumptable_hi - 1, x
|
|
pha
|
|
lda command_CD_jumptable_lo - 1, x
|
|
pha
|
|
|
|
rts
|
|
|
|
#else // HAS_OPCODES_65C02
|
|
|
|
// Use jumptable to go to the command routine
|
|
|
|
asl
|
|
tax
|
|
jmp (command_CD_jumptable - 2, x)
|
|
|
|
#endif
|
|
|
|
|
|
execute_statements_end_of_line:
|
|
|
|
// First check, if we are in direct mode - if so,
|
|
// end the execution and go to main loop
|
|
|
|
ldx CURLIN+1
|
|
inx
|
|
beq_16 basic_main_loop
|
|
|
|
// Advance to the next line - first copy the line number
|
|
// to previous line number
|
|
|
|
lda CURLIN+0
|
|
sta OLDLIN+0
|
|
lda CURLIN+1
|
|
sta OLDLIN+1
|
|
|
|
// Advance the basic line pointer to the next line; if end,
|
|
// go to the main loop
|
|
|
|
jsr basic_follow_link_to_next_line
|
|
|
|
lda OLDTXT+0
|
|
ora OLDTXT+1
|
|
beq_16 basic_main_loop
|
|
|
|
// FALLTROUGH
|
|
|
|
execute_line:
|
|
|
|
// Check if pointer is null, if so, we are at the end of the program
|
|
|
|
ldy #0
|
|
jsr peek_line_pointer_null_check
|
|
bcc_16 basic_main_loop // branch if end of program reached
|
|
|
|
// Skip pointer and line number to get address of first statement
|
|
|
|
lda OLDTXT+0
|
|
clc
|
|
adc #$04
|
|
sta TXTPTR+0
|
|
lda OLDTXT+1
|
|
adc #$00
|
|
sta TXTPTR+1
|
|
|
|
ldy #$02
|
|
|
|
#if CONFIG_MEMORY_MODEL_60K
|
|
ldx #<OLDTXT
|
|
jsr peek_under_roms
|
|
#else // CONFIG_MEMORY_MODEL_38K
|
|
lda (OLDTXT),y
|
|
#endif
|
|
|
|
sta CURLIN+0
|
|
iny
|
|
|
|
#if CONFIG_MEMORY_MODEL_60K
|
|
jsr peek_under_roms
|
|
#else // CONFIG_MEMORY_MODEL_38K
|
|
lda (OLDTXT),y
|
|
#endif
|
|
|
|
sta CURLIN+1
|
|
|
|
jmp execute_statements
|
|
|
|
|
|
execute_statements_var_assign:
|
|
|
|
// XXX here we should handle variable assignments, probably in a separate file
|
|
|
|
// Prevent wedges from being executed within a program
|
|
|
|
#if CONFIG_TAPE_WEDGE
|
|
cmp #$40
|
|
beq_16 do_DIRECT_MODE_ONLY_error
|
|
#endif
|
|
#if CONFIG_DOS_WEDGE
|
|
cmp #$5F
|
|
beq_16 do_DIRECT_MODE_ONLY_error
|
|
#endif
|
|
|
|
jmp do_SYNTAX_error
|