Fixed hardware detection.

The previous chip detection was inspired by the old IP65 driver code. For some reason it didn't work as expected. The new code is simpler and based on this statement in the chip datasheet: "The upper byte always reads as 33h and can be used to help determine the I/O location of the LAN91C96."

cpu/6502/net/lan91c96.S

@@ -67,7 +67,7 @@ len:	.res	2		; Frame length
 	.else
 
 	.include "zeropage.inc"
-reg	:=	ptr1		;  Address of register base
+reg	:=	ptr1		; Address of register base
 ptr	:=	ptr2		; Indirect addressing pointer
 len	:=	ptr3		; Frame length
 
@@ -168,16 +168,24 @@ init:
 	inc ptr+1
 	bcs :-			; Always
 
+	; Check bank select register upper byte to always read as $33
+:	ldy #$00
+fixup01:sty ethbsr+1
+fixup02:lda ethbsr+1
+	cmp #$33
+	beq :+
+	sec
+	rts
+
 	; Reset ETH card
-:	lda #$00		; Bank 0
-fixup01:sta ethbsr
+:				; Bank 0
+fixup03:sty ethbsr
 
 	lda #%10000000		; Software reset
-fixup02:sta ethrcr+1
+fixup04:sta ethrcr+1
 
-	ldy #$00
-fixup03:sty ethrcr
-fixup04:sty ethrcr+1
+fixup05:sty ethrcr
+fixup06:sty ethrcr+1
 
 	; Delay
 :	cmp ($FF,x)		; 6 cycles
@@ -189,21 +197,12 @@ fixup04:sty ethrcr+1
 	; Enable transmit and receive
 	lda #%10000001		; Enable transmit TXENA, PAD_EN
 	ldx #%00000011		; Enable receive, strip CRC ???
-fixup05:sta ethtcr
-fixup06:stx ethrcr+1
+fixup07:sta ethtcr
+fixup08:stx ethrcr+1
 
 	lda #$01		; Bank 1
-fixup07:sta ethbsr
+fixup09:sta ethbsr
 
-	; Check ISA mode base address register for reset values
-	lda #$18^67		; I/O base $300 + ROM $CC000
-fixup08:eor ethbar
-fixup09:eor ethbar+1
-	beq :+
-	sec
-	rts
-
-:
 fixup10:lda ethcr+1
 	ora #%00010000		; No wait (IOCHRDY)
 fixup11:sta ethcr+1