[KERNAL] use dedicated tmp memory location for kbd_scan (#298)

X16Community · Mar 12, 2024 · eff3963 · eff3963
1 parent 2d07153
commit eff3963
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Showing 3 changed files with 15 additions and 9 deletions.
diff --git a/cfg/kernal-x16.cfgtpl b/cfg/kernal-x16.cfgtpl
@@ -10,6 +10,7 @@ MEMORY {
 SEGMENTS {
 	ZPKERNAL:   load = ZPKERNAL, type = zp;
 	ZPCHANNEL:  load = ZPKERNAL, type = zp;
+	ZPKBD:      load = ZPKERNAL, type = zp;
 	ZPFONTS:    load = ZPKERNAL, type = zp;
 
 	KVAR:       load = KVAR,     type = bss;

diff --git a/cfg/x16.cfginc b/cfg/x16.cfginc
@@ -13,9 +13,9 @@
 
 /* zero page */
 /*        start = $0000, size = $0080; # available to the user */
-ZPKERNAL: start = $0080, size = $0010; # KERNAL
-ZPDOS:    start = $0090, size = $000B; # DOS
-/*        start = $009B, size = $000C; # reserved for DOS or BASIC growth */
+ZPKERNAL: start = $0080, size = $0011; # KERNAL
+ZPDOS:    start = $0091, size = $000B; # DOS
+/*        start = $009C, size = $000B; # reserved for DOS or BASIC growth */
 ZPAUDIO:  start = $00A7, size = $0002; # AUDIO
 ZPMATH:   start = $00A9, size = $002B; # MATH
 ZPBASIC:  start = $00D4, size = $002B; # BASIC (last byte used: $FE)

diff --git a/kernal/drivers/x16/ps2kbd.s b/kernal/drivers/x16/ps2kbd.s
@@ -58,6 +58,11 @@ KBDNAM_LEN = 14
 .segment "ZPKERNAL" : zeropage
 ckbtab:	.res 2           ;    used for keyboard lookup
 
+.segment "ZPKBD": zeropage
+kbtmp:  .res 1           ;    meant for exclusive use in kbd_scan
+                         ;   The routine formerly used tmp2 which
+                         ;   can conflict with usage outside of the ISR
+
 .segment "KVARSB0"
 
 prefix:	.res 1           ;    PS/2: prefix code (e0/e1)
@@ -320,7 +325,7 @@ is_reg_key:
 	; Pause/break key?
 	cmp #KEYCODE_PAUSEBRK
 	bne :+
-	
+
 	ldx #$03 * 2 ; stop (-> run)
 	lda shflag
 	lsr ; shift -> C
@@ -354,7 +359,7 @@ cont: 	jsr find_table
 ; the tables use modifiers $C6 (Alt/AltGr) and $C7 (Shift+Alt/AltGr).
 ; If we don't find a table and the modifier is (Shift+)Alt/AltGr,
 ; try these modifier codes.
-	lda tmp2
+	lda kbtmp
 	cmp #$82
 	beq @again
 	cmp #$83
@@ -377,7 +382,7 @@ cont: 	jsr find_table
 ; scan dead key tables; if nothing found, it's unassigned
 @maybe_dead:
 	sty dk_scan
-	lda tmp2
+	lda kbtmp
 	sta dk_shift
 @skip:	rts
 
@@ -496,14 +501,14 @@ handle_caps:
 
 find_table:
 .assert keymap_data = $a000, error; so we can ORA instead of ADC and carry
-	sta tmp2
+	sta kbtmp
 	lda #<keymap_data
 	sta ckbtab
 	lda #>keymap_data
 	sta ckbtab+1
 	ldx #TABLE_COUNT
 @loop:	lda (ckbtab)
-	cmp tmp2
+	cmp kbtmp
 	beq @ret        ; .C = 1: found
 	lda ckbtab
 	eor #$80
@@ -571,4 +576,4 @@ modifier_shift_states:
 	.byt MODIFIER_ALTGR
 	.byt MODIFIER_CTRL
 	.byt MODIFIER_WIN
-	.byt MODIFIER_4080
+	.byt MODIFIER_4080