improved syntax checking in BASIC

2020-07-09 22:23:04 +02:00
1 parent 2a597b59e2
commit defd079b2e
@@ -9,4 +9,4 @@ cmd_clr:

 	// CLR command does not stop execution (confirmed on a C64)

-	jmp execute_statements
+	jmp end_of_statement
@@ -52,7 +52,7 @@ cmd_load_no_error:
 	// For VERIFY - this is it

 	lda VERCKB
-	bne_16 execute_statements
+	bne_16 end_of_statement

 	// C64 BASIC apparently does not clear variables after a LOAD in the
 	// middle of a program. For safety, we do.
@@ -89,4 +89,6 @@ cmd_print_new_line_done:

 cmd_print_done:

-	jmp execute_statements
+	// Execute next statement
+
+	jmp end_of_statement
@@ -9,4 +9,4 @@ cmd_restore:

 	// RESTORE command does not stop execution (confirmed on a C64)

-	jmp execute_statements
+	jmp end_of_statement
@@ -38,6 +38,6 @@ cmd_save_do: // entry point for BSAVE
 	jsr JSAVE
 	bcs_16 do_kernal_error

-	// The end
+	// Execute next statement

-	jmp execute_statements
+	jmp end_of_statement
@@ -62,7 +62,7 @@ cmd_sys_setup_call:
 	// Call the routine.
 	jsr USRPOK
 	
-	jmp execute_statements
+	jmp end_of_statement


 	//
@@ -37,6 +37,6 @@ cmd_bload:
 	jsr JLOAD
 	bcs_16 do_kernal_error

-	// XXX when number parsing is done, change to continue execution
+	// Execute next statement

-	jmp shell_main_loop
+	jmp end_of_statement
@@ -7,4 +7,7 @@ cmd_clear:

 	jsr clear_screen

-	jmp execute_statements
+	// Execute next statement
+
+	jmp end_of_statement
+
@@ -6,7 +6,7 @@
 cmd_cold:

 	jsr helper_ask_if_sure
-	bcs_16 execute_statements
+	bcs_16 end_of_statement

 	jsr JCLALL                         // for extra safety
 	jmp (vector_reset)                 // hardware CPU vector
@@ -7,4 +7,7 @@ cmd_dispose:

 	jsr varstr_garbage_collect

-	jmp execute_statements
+	// Execute next statement
+
+	jmp end_of_statement
+
@@ -46,6 +46,6 @@ cmd_merge_no_error:

 	jsr update_LINKPRG_VARTAB_do_clr

-	// XXX when number parsing is done, change to continue execution
+	// Execute next statement

-	jmp shell_main_loop
+	jmp end_of_statement
@@ -20,8 +20,8 @@ cmd_fast:

 	lda #$41
 	sta CPU_D6510
+	jmp end_of_statement

-	jmp execute_statements

 #elif CONFIG_MB_ULTIMATE_64

@@ -30,12 +30,12 @@ cmd_fast:
 cmd_slow:

 	sta SCPU_SPEED_NORMAL
-	jmp execute_statements
+	jmp end_of_statement

 cmd_fast:

 	sta SCPU_SPEED_TURBO
-	jmp execute_statements
+	jmp end_of_statement

 #elif CONFIG_PLATFORM_COMMODORE_64

@@ -60,8 +60,7 @@ cmd_fast:
 	lda #$01
 !:
 	sta VIC_CLKRATE
-
-	jmp execute_statements
+	jmp end_of_statement

 #else

@@ -0,0 +1,32 @@
+// #LAYOUT# STD *       #TAKE
+// #LAYOUT# *   BASIC_0 #TAKE
+// #LAYOUT# *   *       #IGNORE
+
+//
+// Executes the next command - after previous got finished
+//
+
+
+end_of_statement:
+	jsr fetch_character
+
+	cmp #$3A                           // check for colon
+	beq end_of_statement_next
+
+	cmp #$00                           // check for end of the line
+	beq_16 execute_statements_end_of_line
+
+	cmp #$20                           // check for space
+	beq end_of_statement
+
+	// Unexpectyed character
+
+	jmp do_SYNTAX_error
+
+end_of_statement_next:
+
+	// Go to next statement
+
+	// XXX this should be speed-optimized, so that no unconsume is necessary
+	jsr unconsume_character
+	jmp execute_statements
@@ -9,8 +9,6 @@

 end_of_statement_check:

-	// XXX this can probably be size-optimized
-
 	ldy #$00

 #if CONFIG_MEMORY_MODEL_60K