various cleanups

2019-10-11 18:14:12 +02:00
1 parent ce8c84a20c
commit f522b82219
@@ -1,8 +1,9 @@
+
 // Key board matrixes: unshifted, shifted, control and C= modified
 // 64 bytes for each


-keyboard_matrixes:
+keyboard_matrix:
 	// Unshifted matrix built by refering to
 	// Compute's Mapping the 64 p38-39
 	// and C64 PRG pages 379-381
@@ -69,4 +70,3 @@ keyboard_matrix_lookup:
 	.byte $C0 		// Vendor + SHIFT
 	.byte $80		// Vendor+ CTRL
 	.byte $80		// Vendor + CTRL + SHIFT
-
@@ -14,7 +14,7 @@
 chkin_real:

 	// Store Y for preservation
-	_phy
+	phy_trash_a

 	// Reset status
 	jsr kernalstatus_reset
@@ -44,7 +44,7 @@ chrin_done_fail:
 chrin_keyboard:

 	// Save X
-	_phx
+	phx_trash_a

 chrin_repeat:

@@ -64,7 +64,7 @@ chrin_repeat:
 	// Return carriage return and clear pending input flag
 	lda #$00
 	sta CRSW
-	_plx
+	plx_trash_a
 	clc
 	lda #$0d
 	rts
@@ -72,7 +72,7 @@ chrin_repeat:
 not_end_of_input:
 	// Return next byte of waiting input and advance index
 	tay
-	_plx
+	plx_trash_a
 	lda (LXSP),y
 	jsr screen_code_to_petscii
 	inc CRSW
@@ -123,7 +123,7 @@ read_from_keyboard:
 	sta CRSW
 	// Return first char of line
 	ldy #$00
-	_plx
+	plx_trash_a
 	lda (LXSP),y
 	jsr screen_code_to_petscii
 	clc
@@ -133,7 +133,7 @@ empty_line:
 	// For an empty line, just return the carriage return
 	// (and don't forget to actually print the carriage return, so that
 	// the cursor advances and screen scrolls as required)
-	_plx
+	plx_trash_a
 	clc
 	lda #$0d
 	rts
@@ -12,7 +12,7 @@
 clall_real:

 	// Store .Y register
-	_phy
+	phy_trash_a

 	// Original routine probably just sets LDTND to 0, but this is not really safe,
 	// so we actually close all the channels; at least IDE64 does the same for
@@ -26,7 +26,7 @@ clall_real:
 	jmp !-
 !:
 	// Restore .Y register
-	_ply
+	ply_trash_a

 	// 'C64 Programmers Reference Guide', page 281, claims it calls CLRCHN too
 	jsr CLRCHN
@@ -17,8 +17,8 @@ CHROUT:
 	// don't get modified, in agreement with C64 PRG's
 	// description of CHROUT)

-	_phx
-	_phy
+	phx_trash_a
+	phy_trash_a

 	php

@@ -45,8 +45,8 @@ chrout_done_fail:
 	plp

 	// Restore X and Y
-	_ply
-	_plx
+	ply_trash_a
+	plx_trash_a

 	sec // indicate failure
 	rts
@@ -56,8 +56,8 @@ chrout_done_unknown_device:
 	plp

 	// Restore X and Y
-	_ply
-	_plx
+	ply_trash_a
+	plx_trash_a

 	// End wioth error
 	jmp lvs_device_not_found_error
@@ -67,8 +67,8 @@ chrout_done_success:
 	plp

 	// Restore X and Y
-	_ply
-	_plx
+	ply_trash_a
+	plx_trash_a

 	lda SCHAR
 	clc // indicate success
@@ -14,8 +14,8 @@ iec_return_success:
 	lda #$00
 	sta C3PO
 	// Restore registers
-	_ply
-	_plx
+	ply_trash_a
+	plx_trash_a
 	// Report success
 	clc
 	rts
@@ -28,7 +28,7 @@ iec_return_DEVICE_NOT_FOUND:
 	lda #$00
 	sta C3PO
 	// Restore registers
-	_ply
-	_plx
+	ply_trash_a
+	plx_trash_a
 	// Report error
 	jmp kernalerror_DEVICE_NOT_FOUND
@@ -7,8 +7,8 @@
 iec_rx_byte:

 	// Store .X and .Y on the stack - preserve them
-	_phx
-	_phy
+	phx_trash_a
+	phy_trash_a

 	// Timing is critical here - execute on disabled IRQs
 	// The best practice would be to do PHP first, but it seems this is not
@@ -5,8 +5,8 @@
 iec_turnaround_to_listen:

 	// Store .X and .Y on the stack - preserve them
-	_phx
-	_phy
+	phx_trash_a
+	phy_trash_a

 	// Timing is critical here - execute on disabled IRQs
 	php
@@ -5,8 +5,8 @@
 iec_turnaround_to_talk:

 	// Store .X and .Y on the stack - preserve them
-	_phx
-	_phy
+	phx_trash_a
+	phy_trash_a

 	// Timing is critical here - execute on disabled IRQs
 	php
@@ -10,8 +10,8 @@
 iec_tx_byte:

 	// Store .X and .Y on the stack - preserve them
-	_phx
-	_phy
+	phx_trash_a
+	phy_trash_a

 	// Notify all devices that we are going to send a byte
 	// and it is going to be a data byte (released ATN)
@@ -10,8 +10,8 @@
 iec_tx_command:

 	// Store .X and .Y on the stack - preserve them
-	_phx
-	_phy
+	phx_trash_a
+	phy_trash_a

 	// Notify all devices that we are going to send a byte
 	// and it is going to be a command (pulled ATN)
@@ -6,8 +6,8 @@
 iec_tx_command_finalize:

 	// Store .X and .Y on the stack - preserve them
-	_phx
-	_phy
+	phx_trash_a
+	phy_trash_a

 	// Give device some time to complete command reception, release ATN,
 	// give it some time again before (possible) next command
@@ -12,7 +12,7 @@ return_from_interrupt:
 	// Restore registers and return
 	// Sequence according to Compute's Mapping the 64 p73

-	_ply
-	_plx
+	ply_trash_a
+	plx_trash_a
 	pla
 	rti
@@ -6,8 +6,8 @@ default_nmi_handler:

 	// Save registers, sequence according to Compute's Mapping the Commodore 64, page 73
 	pha
-	_phx
-	_phy
+	phx_trash_a
+	phy_trash_a

 	// XXX: RS-232 support is not implemented

@@ -11,8 +11,8 @@ hw_entry_irq:

 	// Save registers, sequence according to Compute's Mapping the Commodore 64, page 73
 	pha
-	_phx
-	_phy
+	phx_trash_a
+	phy_trash_a

 #if CONFIG_CPU_MOS_6502 && CONFIG_BCD_SAFE_INTERRUPTS
 	cld // clear decimal flag to allow using it without disabling interrupts
@@ -50,6 +50,22 @@

 // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/

+	// Low memory variables
+
+	// Reuse RS232 variables, since they should not be used by other things.
+	// Carefully avoid $A7 which is used by 64NET
+	.label KeyQuantity       = $A8  // 1 byte
+	.label BufferNew         = $A9  // 3 bytes
+	.label TempZP            = $B6  // 1 byte
+	// These should be initialized in CINIT to $FF
+	.label BufferQuantity    = $B4  // 1 byte
+	.label BufferOld         = $293 // 3 bytes
+	.label Buffer 	         = $297 // 4 bytes
+
+	// $250-$258 is the 81st - 88th characters in BASIC input, a carry over from VIC-20
+	// and not used on C64, so safe for us to use, probably.
+	.label ScanResult = $250 // 8 bytes
+
 	// Operational Variables
 	.const MaxKeyRollover = 3

@@ -102,7 +118,7 @@ accept_key:
 	and #$3f
 	ora keyboard_matrix_lookup,x
 	tax
-	lda keyboard_matrixes,x
+	lda keyboard_matrix,x
 	// But don't insert $00 characters
 	beq sk_nokey

@@ -519,4 +535,4 @@ KeyRepeatWait:
 	jmp ConsiderNextKey


-#endif // #if CONFIG_SCNKEY_TWW_CTR
+#endif // CONFIG_SCNKEY_TWW_CTR