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Avoid access to the address register during auto-increment.

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It cannot be ruled out that access to the address register triggers
an address auto-increment. Therefore a temporary address register
shadow is introduced to replace the access to the address regsiter.

Additionally there are several minor beautifications.
This commit is contained in:
Oliver Schmidt 2013-12-03 21:31:43 +01:00
parent 737d5fd6dc
commit 9cdc6da040
1 changed files with 19 additions and 14 deletions
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33
cpu/6502/net/w5100.S
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@ -79,7 +79,7 @@ fixup: .byte fixup02-fixup01, fixup03-fixup02, fixup04-fixup03
.byte fixup17-fixup16, fixup18-fixup17, fixup19-fixup18
.byte fixup20-fixup19, fixup21-fixup20, fixup22-fixup21
.byte fixup23-fixup22, fixup24-fixup23, fixup25-fixup24
.byte fixup26-fixup25, fixup27-fixup26
.byte fixup26-fixup25
fixups = * - fixup
@ -181,7 +181,7 @@ fixup09:lda data
: tax
rts
; Socket RX Received Size Register: != 0 ?
; Socket 0 RX Received Size Register: != 0 ?
: ldy #$26 ; Socket RX Received Size Register
jsr set_addrsocket0
fixup10:lda data ; Hibyte
@ -199,9 +199,13 @@ fixup11:ora data ; Lobyte
; ldy #$28 ; Socket RX Read Pointer Register
; jsr set_addrsocket0
; Calculate and set pyhsical address
; Calculate and set physical address
jsr set_addrphysical
; Move physical address shadow to $F000-$FFFF
ora #>$F000
tax
; Read MAC raw 2byte packet size header
jsr get_datacheckaddr ; Hibyte
sta adv+1
@ -241,8 +245,8 @@ fixup11:ora data ; Lobyte
; Advance pointer register
common: jsr set_addrsocket0
tay ; Save command
lda reg
clc
lda reg
adc adv
tax
lda reg+1
@ -283,7 +287,7 @@ fixup15:lda data
bne :-
; Socket 0 TX Free Size Register: < length ?
: ldy #$20
: ldy #$20 ; Socket TX Free Size Register
jsr set_addrsocket0
fixup16:lda data ; Hibyte
fixup17:ldx data ; Lobyte
@ -318,8 +322,8 @@ exit:
set_addrphysical:
fixup18:lda data ; Hibyte
fixup19:ldy data ; Lobyte
sta reg+1
sty reg
sta reg+1
and #>$1FFF ; Socket Mask Address (hibyte)
ora bas ; Socket Base Address (hibyte)
tax
@ -341,10 +345,11 @@ set_addrbase:
get_datacheckaddr:
fixup22:lda data
fixup23:ldx addr ; Hibyte
cpx lim ; Socket memory limit (hibyte)
bcs set_addrbase
rts
iny ; Physical address shadow (lobyte)
bne :+
inx ; Physical address shadow (hibyte)
beq set_addrbase
: rts
;---------------------------------------------------------------------
@ -380,10 +385,10 @@ mov_data:
; R/W without address wraparound possible because
; highest R/W address > actual R/W address ?
; sec
fixup24:sbc addr+1 ; Lobyte
fixup23:sbc addr+1 ; Lobyte
tay
txa
fixup25:sbc addr ; Hibyte
fixup24:sbc addr ; Hibyte
tax
tya
bcs :+
@ -444,7 +449,7 @@ rw_data:eor #$FF ; Two's complement part 1
; Read data
:
fixup26:lda data
fixup25:lda data
sta (ptr),y
iny
bne :-
@ -455,7 +460,7 @@ fixup26:lda data
; Write data
: lda (ptr),y
fixup27:sta data
fixup26:sta data
iny
bne :-
inc ptr+1