initial support for Mega65 extra ROM

2020-01-10 22:03:10 +01:00
1 parent 7539c6b072
commit 4d56864327
@@ -1,3 +1,5 @@
+#if ROM_LAYOUT_STD || (ROM_LAYOUT_M65 && SEGMENT_KERNAL_0)
+

 default_irq_handler:

@@ -42,3 +44,6 @@ default_irq_handler_end_tape:

 	// Acknowledge CIA interrupt and return
 	jmp clear_cia1_interrupt_flag_and_return_from_interrupt
+
+
+#endif // ROM layout
@@ -1,3 +1,5 @@
+#if ROM_LAYOUT_STD || (ROM_LAYOUT_M65 && SEGMENT_KERNAL_0)
+
 // https://csdb.dk/forums/index.php?roomid=11&topicid=5776
 // Clear the CIA1 interrupt flag, and then fall through to
 // the return from interrupt routine
@@ -9,3 +11,6 @@ clear_cia1_interrupt_flag_and_return_from_interrupt:
 	ldy CIA1_ICR

 	// FALL THROUGH to $EA81
+
+
+#endif // ROM layout
@@ -1,8 +1,10 @@
+#if ROM_LAYOUT_STD || (ROM_LAYOUT_M65 && SEGMENT_KERNAL_0)
+
 // The IRQ is a commonly messed with thing on the C64,
 // so we need to handle entry points that are commonly
 // relied upon, including:
 // $EA31 - Standard IRQ routine
-// $EA61 - Check keyboard, but don't update timer? https://github.com/cc65/cc65/issues/324
+// $EA61 - Check keyboard, but do not update timer? https://github.com/cc65/cc65/issues/324
 // $EA81 - https://www.lemon64.com/forum/viewtopic.php?t=2112&sid=6ea01982b26da69783120a7923ca46fb
 // Also the $0314 vector is widely used (e.g., https://www.lemon64.com/forum/viewtopic.php?t=2112&sid=6ea01982b26da69783120a7923ca46fb)

@@ -10,9 +12,12 @@
 return_from_interrupt:

 	// Restore registers and return
-	// Sequence according to Compute's Mapping the 64 p73
+	// Sequence according to Computes Mapping the 64 p73

 	ply_trash_a
 	plx_trash_a
 	pla
 	rti
+
+
+#endif // ROM layout
@@ -1,10 +1,11 @@
+#if ROM_LAYOUT_STD || (ROM_LAYOUT_M65 && SEGMENT_KERNAL_0)

 default_nmi_handler:

-	// Implemented according to Compute's Mapping the Commodore 64, page 74
+	// Implemented according to Computes Mapping the Commodore 64, page 74
 	// and to https://www.c64-wiki.com/wiki/Interrupt

-	// Save registers, sequence according to Compute's Mapping the Commodore 64, page 73
+	// Save registers, sequence according to Computes Mapping the Commodore 64, page 73
 	pha
 	phx_trash_a
 	phy_trash_a
@@ -25,8 +26,11 @@ default_nmi_handler:
 	bcs !+
 	jmp return_from_interrupt // no STOP pressed
 !:
-	// STOP + RESTORE - clean the address of the BRK instruction (it's not BRK) first
+	// STOP + RESTORE - clean the address of the BRK instruction (it is not BRK) first
 	lda #$00
 	sta CMP0+0
 	sta CMP0+1
 	jmp (CBINV)
+
+
+#endif // ROM layout
@@ -1,9 +1,10 @@
+#if ROM_LAYOUT_STD || (ROM_LAYOUT_M65 && SEGMENT_KERNAL_0)

 default_brk_handler:

-	// Implemented according to Compute's Mapping the Commodore 64, pages 73-74
+	// Implemented according to Computes Mapping the Commodore 64, pages 73-74

-	sei // disable IRQs, to be sure they won't interfere
+	sei // disable IRQs, to be sure they wont interfere

 	ldx #$00
 	sta VIC_SCROLX // turn the display off - we want as little screen artifacts as possible
@@ -13,8 +14,8 @@ default_brk_handler:
 	jsr JRESTOR
 	jsr JIOINIT

-	// Original routine calls just a part of CINT - but I'm not sure which one. Most likely it
-	// skips the PAL/NTSC check by calling $E518. I suspect bug in the original ROM, let's
+	// Original routine calls just a part of CINT - but I am not sure which one. Most likely it
+	// skips the PAL/NTSC check by calling $E518. I suspect bug in the original ROM, lets
 	// call the whole CINT, just to be sure everything is initialized.

 	jsr CINT
@@ -22,3 +23,6 @@ default_brk_handler:
 	cli

 	jmp (IBASIC_WARM_START)
+
+
+#endif // ROM layout
@@ -1,4 +1,9 @@
+#if ROM_LAYOUT_STD || (ROM_LAYOUT_M65 && SEGMENT_KERNAL_0)
+
 // $FFFA - CPU NMI Hanlder
 // Uncontrovertial as this is also a CPU requirement.

 	.word hw_entry_nmi
+
+
+#endif // ROM layout
@@ -1,5 +1,10 @@
+#if ROM_LAYOUT_STD || (ROM_LAYOUT_M65 && SEGMENT_KERNAL_0)
+
 // $FFFE - CPU IRQ Vector.
 // This is non-controvertial, as it is a 6502 CPU requirement, and we just have to point
 // it to whatever IRQ routine we make.

 	.word hw_entry_irq
+
+
+#endif // ROM layout
@@ -1,3 +1,5 @@
+#if ROM_LAYOUT_STD || (ROM_LAYOUT_M65 && SEGMENT_KERNAL_0)
+

 hw_entry_irq:

@@ -5,11 +7,11 @@ hw_entry_irq:
 	// so we need to handle entry points that are commonly
 	// relied upon, including:
 	// $EA31 - Standard IRQ routine
-	// $EA61 - Check keyboard, but don't update timer? https://github.com/cc65/cc65/issues/324
+	// $EA61 - Check keyboard, but do not update timer? https://github.com/cc65/cc65/issues/324
 	// $EA81 - https://www.lemon64.com/forum/viewtopic.php?t=2112&sid=6ea01982b26da69783120a7923ca46fb
 	// Also the $0314 vector is widely used (e.g., https://www.lemon64.com/forum/viewtopic.php?t=2112&sid=6ea01982b26da69783120a7923ca46fb)

-	// Save registers, sequence according to Compute's Mapping the Commodore 64, page 73
+	// Save registers, sequence according to Computes Mapping the Commodore 64, page 73
 	pha
 	phx_trash_a
 	phy_trash_a
@@ -46,3 +48,6 @@ irq_handler_brk:

 	// Interrupt caused by BRK
 	jmp (CBINV)
+
+
+#endif // ROM layout
@@ -1,7 +1,9 @@
+#if ROM_LAYOUT_STD || (ROM_LAYOUT_M65 && SEGMENT_KERNAL_0)
+

 hw_entry_nmi:

-	sei // don't allow IRQ to interfere, see https://www.c64-wiki.com/wiki/Interrupt
+	sei // do not allow IRQ to interfere, see https://www.c64-wiki.com/wiki/Interrupt

 #if CONFIG_CPU_MOS_6502 && CONFIG_BCD_SAFE_INTERRUPTS
 	cld // clear decimal flag to allow using it without disabling interrupts
@@ -18,3 +20,6 @@ hw_entry_nmi:
 	// Vector not initialized - call default interrupt routine
 	pla
 	jmp default_nmi_handler
+
+
+#endif // ROM layout