[KERNAL] implement native-capable jsrfar (#283)

* [KERNAL] implement native-capable jsrfar * native jsrfar falls back to old code if in emulated mode * fix off-by-one error * fix up some logic, jmpfr need only be in one place * Save a couple cycles here * save a few more cycles w/ carry assumptions * add assert for jsrfar3n * saved one more cycle * trivial changes * trivial changes * updates to comments * updates to comments * no need to preserve X in the native jsrfar * fix stack misalignment issue in a 16-bit jsrfar call * requested changes
X16Community · Mar 8, 2024 · b60181a · b60181a
1 parent c605423
commit b60181a
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Showing 10 changed files with 131 additions and 16 deletions.
diff --git a/cfg/audio-x16.cfgtpl b/cfg/audio-x16.cfgtpl
@@ -1,8 +1,8 @@
 MEMORY {
 	#include "x16.cfginc"
 
-	ROM:         start = $C000, size = $3B00, fill=yes, fillval=$AA;
-	KSUP_CODE10: start = $FB00, size = $03A8, fill=yes, fillval=$AA;
+	ROM:         start = $C000, size = $3A80, fill=yes, fillval=$AA;
+	KSUP_CODE10: start = $FA80, size = $0428, fill=yes, fillval=$AA;
 	KSUP_VEC10:  start = $FEA8, size = $0158, fill=yes, fillval=$AA;
 
 }

diff --git a/cfg/bannex-x16.cfgtpl b/cfg/bannex-x16.cfgtpl
@@ -1,8 +1,8 @@
 MEMORY {
 	#include "x16.cfginc"
 
-	ANNEX:     start = $C000, size = $3B00, fill=yes, fillval=$AA;
-	KSUP_CODE12: start = $FB00, size = $03A8, fill=yes, fillval=$AA;
+	ANNEX:     start = $C000, size = $3A80, fill=yes, fillval=$AA;
+	KSUP_CODE12: start = $FA80, size = $0428, fill=yes, fillval=$AA;
 	KSUP_VEC12:  start = $FEA8, size = $0158, fill=yes, fillval=$AA;
 }
 

diff --git a/cfg/codex-x16.cfgtpl b/cfg/codex-x16.cfgtpl
@@ -1,11 +1,11 @@
 MEMORY {
 	#include "x16.cfginc"
 
-    MAIN:     file = %O, define = yes, start = $C000, size = $3AE2, fill=yes  fillval=$A3;
+    MAIN:     file = %O, define = yes, start = $C000, size = $3A72, fill=yes  fillval=$A3;
     RWRAM:    file = "",               start = $0400, size = $3FF;
     BANK:     file = "",               start = $A000, size = $2000;
-    CODEX_VECS: start = $FAE2, size = $001E, fill=yes, fillval=$A0;
-    KSUP_CODE2: start = $FB00, size = $03A8, fill=yes, fillval=$A1;
+    CODEX_VECS: start = $FA72, size = $001E, fill=yes, fillval=$A0;
+    KSUP_CODE2: start = $FA80, size = $0418, fill=yes, fillval=$A1;
     KSUP_VEC2:  start = $FEA8, size = $0158, fill=yes, fillval=$A2;
 }
 

diff --git a/cfg/kernal-x16.cfgtpl b/cfg/kernal-x16.cfgtpl
@@ -68,6 +68,7 @@ SEGMENTS {
 	VERA_DRV: load = KERNAL,   type = ro;
 	PALETTE:  load = KERNAL,   type = ro, align = $100;
 	KRAMJFAR: load = KERNAL,   run = KRAMJFAR, type = ro, define = yes;
+	KJFAR816: load = KERNAL,   run = KJFAR816, type = ro, define = yes;
 	KERNRAM2: load = KERNAL,   run = KERNRAM2, type = ro, define = yes;
 	KRAM816:  load = KERNAL,   run = KRAM816,  type = ro, define = yes;
 	KRAM02B:  load = KERNAL,   run = KRAM02B,  type = ro, define = yes;

diff --git a/cfg/monitor-x16.cfgtpl b/cfg/monitor-x16.cfgtpl
@@ -3,8 +3,8 @@ MEMORY {
 
 	L0220:    start = $0220, size = $0019; # overlaps with top end of BASIC input line only
 
-	BANK5:      start = $C000, size = $3B00, fill=yes, fillval=$AA;
-	KSUP_CODE2: start = $FB00, size = $03A8, fill=yes, fillval=$AA;
+	BANK5:      start = $C000, size = $3A80, fill=yes, fillval=$AA;
+	KSUP_CODE2: start = $FA80, size = $0428, fill=yes, fillval=$AA;
 	KSUP_VEC2:  start = $FEA8, size = $0158, fill=yes, fillval=$AA;
 }
 

diff --git a/cfg/util-x16.cfgtpl b/cfg/util-x16.cfgtpl
@@ -4,8 +4,8 @@ MEMORY {
 	HEXEDITZP:   start = $0022, size = $005E, fill=no;
 	HEXEDITBSS:  start = $0200, size = $0050, fill=no;
 	MENUBSS:     start = $0200, size = $0050, fill=no;
-	ROM:         start = $C000, size = $3B00, fill=yes, fillval=$AA;
-	KSUP_CODE11: start = $FB00, size = $03A8, fill=yes, fillval=$AA;
+	ROM:         start = $C000, size = $3A80, fill=yes, fillval=$AA;
+	KSUP_CODE11: start = $FA80, size = $0428, fill=yes, fillval=$AA;
 	KSUP_VEC11:  start = $FEA8, size = $0158, fill=yes, fillval=$AA;
 
 }

diff --git a/cfg/x16.cfginc b/cfg/x16.cfginc
@@ -23,7 +23,8 @@ ZPBASIC:  start = $00D4, size = $002B; # BASIC (last byte used: $FE)
 /* $0200-$02FF: always-available variables and RAM code */
 KVAR:     start = $0200, size = $0095; # KERNAL
 KRAM816S: start = $0295, size = $0003; # KERNAL: 65C816: old stack pointer
-/*        start = $0298, size = $0028; # reserved for KERNAL growth */
+KJFAR816: start = $0298, size = $0019; # KERNAL: jsrfar3n
+/*        start = $02B1, size = $000F; # reserved for KERNAL growth */
 I2CMUTEX: start = $02C0, size = $0001; # I2C MUTEX FLAG
 GRAPHVAR: start = $02C1, size = $0003; # GRAPH BANK VARS
 KRAMJFAR: start = $02C4, size = $001E; # KERNAL: jsrfar3

diff --git a/inc/banks.inc b/inc/banks.inc
@@ -19,6 +19,7 @@ BANK_BASLOAD = $0F
 ; XXX implementation details and need to go away!
 cbdos_flags= $0268
 status     = $0287 ; channel: status byte
+jsrfar3n   = $0298 ; jsrfar: RAM part, 65C816 native
 jsrfar3    = $02c4 ; jsrfar: RAM part
 jmpfr      = $02df ; jsrfar: core jmp instruction
 imparm     = $82   ; jsrfar: temporary byte

diff --git a/inc/jsrfar.inc b/inc/jsrfar.inc
@@ -4,16 +4,23 @@
 ; .word address
 ; .byte bank
 
-	pha             ;reserve 1 byte on the stack
+	php             ;reserve 1 byte on the stack
 	php             ;save registers & status
+
+	sec
+	.byte $c2, $03 ; rep #$03, clear carry/z if 65c816
+	bcc jsrfarn
+
+	clc
+jsrfare:
 	pha
 	phx
 	phy
 
-        tsx
+	tsx
 	lda $106,x      ;return address lo
 	sta imparm
-	clc
+	; carry is clear
 	adc #3
 	sta $106,x      ;and write back with 3 added
 	lda $107,x      ;return address hi
@@ -63,4 +70,74 @@ jsrfar2:
 	pla
 	plp
 	plp
-	rts
+	rts
+
+.pushcpu
+
+.setcpu "65816"
+
+jsrfarn:
+	; carry is clear
+	php
+	sei
+	xce
+	bcc :+
+	xce
+	plp
+	bra jsrfare ; with carry cleared
+:	plp
+	rep #$31    ; force 16 bit memory/index, clear carry
+	.A16
+	.I16
+	pha
+	phy
+
+	lda $07,S   ; fetch return address
+	sta imparm
+	; carry is clear
+	adc #3
+	sta $07,S   ; write back return address+3
+	ldy #1
+	lda (imparm),y
+	sta jmpfr+1
+	cmp #$c000
+	bcc jsrfar1n
+; target is in ROM
+	sep #$20    ; 8 bit accumulator
+	.A8
+	lda rom_bank
+	sta $06,S   ; save original bank onto reserved byte
+	ldy #3
+	lda (imparm),y
+	ply
+	jmp jsrfar3n
+
+; target is in RAM
+jsrfar1n:
+	sep #$20   ; 8 bit accumulator
+	.A8
+	lda ram_bank
+	sta $06,S  ; save original bank onto reserved byte
+	lda #3
+	lda (imparm),y
+	sta ram_bank
+	rep #$20   ; 16 bit accumulator
+	.A16
+	ply
+	pla
+	plp        ; original register widths popped immediately before call
+	jsr jmpfr
+	php        ; preserve flags immediately after return from call
+	sep #$20   ; 8 bit accumulator
+	.A8
+	pha
+	lda $03,S
+	sta ram_bank
+	lda $02,S  ; overwrite reserved byte
+	sta $03,S  ; with copy of .P
+	pla
+	plp        ; restore flags to state immediately after call
+	plp
+	rts
+
+.popcpu
diff --git a/kernal/drivers/x16/memory.s b/kernal/drivers/x16/memory.s
@@ -8,6 +8,7 @@
 .include "io.inc"
 
 .import __KRAMJFAR_LOAD__, __KRAMJFAR_RUN__, __KRAMJFAR_SIZE__
+.import __KJFAR816_LOAD__, __KJFAR816_RUN__, __KJFAR816_SIZE__
 .import __KERNRAM2_LOAD__, __KERNRAM2_RUN__, __KERNRAM2_SIZE__
 .import __KRAM816_LOAD__, __KRAM816_RUN__, __KRAM816_SIZE__
 .import __KRAM02B_LOAD__, __KRAM02B_RUN__, __KRAM02B_SIZE__
@@ -139,6 +140,11 @@ ramtas:
 	.A16
 	.I16
 
+	ldx #__KJFAR816_LOAD__
+	ldy #__KJFAR816_RUN__
+	lda #(__KJFAR816_SIZE__ - 1)
+	mvn #00,#00
+
 	ldx #__KRAM816_LOAD__
 	ldy #__KRAM816_RUN__
 	lda #(__KRAM816_SIZE__ - 1)
@@ -271,6 +277,35 @@ jsrfar:
 __jmpfr:
 	jmp $ffff
 
+.pushcpu
+.setcpu "65816"
+
+.segment "KJFAR816"
+.assert * = jsrfar3n, error, "jsrfar3n must be at specific address"
+
+;jsrfar3n:
+	.A8
+	.I16
+	sta rom_bank    ;set ROM bank
+	rep #$20
+	.A16
+	pla
+	plp             ; restore all flags immediately before call
+	jsr jmpfr
+	php
+	sep #$20        ; 8 bit accumulator
+	.A8
+	pha             ; Push lower byte of accumulator
+	lda $03,S
+	sta rom_bank    ;restore ROM bank
+	lda $02,S       ;overwrite reserved byte...
+	sta $03,S       ;...with copy of .P
+	pla             ; .B remains unchanged and is thus preserved
+	plp             ; restore flags from state immediately after call
+	plp
+	rts
+
+.popcpu
 
 .segment "KERNRAM2"