Remove received packet(s) to allow to send one.
Behave just like the CS8900A driver: Both the CS8900A and the LAN91C96 dynamically share a buffer for received packets and packets to be send. If the chip is exposed to a network with a lot of broadcasts the shared buffer might fill quicker with received packets than the 6502 reads them (via polling). So we might need to drop some received packets in order to be able to send anything at all.
This commit is contained in:
Oliver Schmidt
parent
da536cb07c
commit
7b3e80a957
|
|
@ -89,7 +89,7 @@ fixup: .byte fixup02-fixup01, fixup03-fixup02, fixup04-fixup03
|
||||||
.byte fixup29-fixup28, fixup30-fixup29, fixup31-fixup30
|
.byte fixup29-fixup28, fixup30-fixup29, fixup31-fixup30
|
||||||
.byte fixup32-fixup31, fixup33-fixup32, fixup34-fixup33
|
.byte fixup32-fixup31, fixup33-fixup32, fixup34-fixup33
|
||||||
.byte fixup35-fixup34, fixup36-fixup35, fixup37-fixup36
|
.byte fixup35-fixup34, fixup36-fixup35, fixup37-fixup36
|
||||||
.byte fixup38-fixup37, fixup39-fixup38, fixup40-fixup39
|
.byte fixup38-fixup37, fixup39-fixup38
|
||||||
|
|
||||||
fixups = * - fixup
|
fixups = * - fixup
|
||||||
|
|
||||||
|
|
@ -272,9 +272,7 @@ fixup22:lda ethdata
|
||||||
bcs :++
|
bcs :++
|
||||||
|
|
||||||
; Yes, skip packet
|
; Yes, skip packet
|
||||||
; Remove and release RX packet from the FIFO
|
jsr releasepacket
|
||||||
lda #%10000000
|
|
||||||
fixup23:sta ethmmucr
|
|
||||||
|
|
||||||
; No packet available
|
; No packet available
|
||||||
lda #$00
|
lda #$00
|
||||||
|
|
@ -285,7 +283,7 @@ fixup23:sta ethmmucr
|
||||||
; Read bytes into buffer
|
; Read bytes into buffer
|
||||||
: jsr adjustptr
|
: jsr adjustptr
|
||||||
:
|
:
|
||||||
fixup24:lda ethdata
|
fixup23:lda ethdata
|
||||||
sta (ptr),y
|
sta (ptr),y
|
||||||
iny
|
iny
|
||||||
bne :-
|
bne :-
|
||||||
|
|
@ -294,8 +292,7 @@ fixup24:lda ethdata
|
||||||
bpl :-
|
bpl :-
|
||||||
|
|
||||||
; Remove and release RX packet from the FIFO
|
; Remove and release RX packet from the FIFO
|
||||||
lda #%10000000
|
jsr releasepacket
|
||||||
fixup25:sta ethmmucr
|
|
||||||
|
|
||||||
; Return packet length
|
; Return packet length
|
||||||
lda len
|
lda len
|
||||||
|
|
@ -313,19 +310,19 @@ send:
|
||||||
; Allocate memory for TX
|
; Allocate memory for TX
|
||||||
txa
|
txa
|
||||||
ora #%00100000
|
ora #%00100000
|
||||||
fixup26:sta ethmmucr
|
fixup24:sta ethmmucr
|
||||||
|
|
||||||
; 8 retries
|
; 8 retries
|
||||||
ldy #$08
|
ldy #$08
|
||||||
|
|
||||||
; Wait for allocation ready
|
; Wait for allocation ready
|
||||||
:
|
:
|
||||||
fixup27:lda ethist
|
fixup25:lda ethist
|
||||||
and #%00001000 ; ALLOC INT
|
and #%00001000 ; ALLOC INT
|
||||||
bne :+
|
bne :+
|
||||||
|
|
||||||
; Shouldn't we do something here to actively free memory,
|
; No space avaliable, skip a received frame
|
||||||
; maybe removing and releasing an RX packet from the FIFO ???
|
jsr releasepacket
|
||||||
|
|
||||||
; And try again
|
; And try again
|
||||||
dey
|
dey
|
||||||
|
|
@ -335,21 +332,21 @@ fixup27:lda ethist
|
||||||
|
|
||||||
; Acknowledge interrupt, is it necessary ???
|
; Acknowledge interrupt, is it necessary ???
|
||||||
: lda #%00001000
|
: lda #%00001000
|
||||||
fixup28:sta ethack
|
fixup26:sta ethack
|
||||||
|
|
||||||
; Set packet address
|
; Set packet address
|
||||||
fixup29:lda etharr
|
fixup27:lda etharr
|
||||||
fixup30:sta ethpnr
|
fixup28:sta ethpnr
|
||||||
|
|
||||||
lda #$00
|
lda #$00
|
||||||
ldx #%01000000 ; AUTO INCR.
|
ldx #%01000000 ; AUTO INCR.
|
||||||
fixup31:sta ethptr
|
fixup29:sta ethptr
|
||||||
fixup32:stx ethptr+1
|
fixup30:stx ethptr+1
|
||||||
|
|
||||||
; Status written by CSMA
|
; Status written by CSMA
|
||||||
lda #$00
|
lda #$00
|
||||||
fixup33:sta ethdata
|
fixup31:sta ethdata
|
||||||
fixup34:sta ethdata
|
fixup32:sta ethdata
|
||||||
|
|
||||||
; Check packet length parity:
|
; Check packet length parity:
|
||||||
; - Even packet length -> carry set -> add 6 bytes
|
; - Even packet length -> carry set -> add 6 bytes
|
||||||
|
|
@ -361,10 +358,10 @@ fixup34:sta ethdata
|
||||||
; The packet contains 3 extra words
|
; The packet contains 3 extra words
|
||||||
lda len
|
lda len
|
||||||
adc #$05 ; Actually 5 or 6 depending on carry
|
adc #$05 ; Actually 5 or 6 depending on carry
|
||||||
fixup35:sta ethdata
|
fixup33:sta ethdata
|
||||||
lda len+1
|
lda len+1
|
||||||
adc #$00
|
adc #$00
|
||||||
fixup36:sta ethdata
|
fixup34:sta ethdata
|
||||||
|
|
||||||
; Send the packet
|
; Send the packet
|
||||||
; ---------------
|
; ---------------
|
||||||
|
|
@ -372,7 +369,7 @@ fixup36:sta ethdata
|
||||||
; Write bytes from buffer
|
; Write bytes from buffer
|
||||||
jsr adjustptr
|
jsr adjustptr
|
||||||
: lda (ptr),y
|
: lda (ptr),y
|
||||||
fixup37:sta ethdata
|
fixup35:sta ethdata
|
||||||
iny
|
iny
|
||||||
bne :-
|
bne :-
|
||||||
inc ptr+1
|
inc ptr+1
|
||||||
|
|
@ -390,13 +387,13 @@ fixup37:sta ethdata
|
||||||
|
|
||||||
; No
|
; No
|
||||||
: lda #$00
|
: lda #$00
|
||||||
fixup38:sta ethdata ; Fill byte
|
fixup36:sta ethdata ; Fill byte
|
||||||
:
|
:
|
||||||
fixup39:sta ethdata ; Control byte
|
fixup37:sta ethdata ; Control byte
|
||||||
|
|
||||||
; Add packet to FIFO
|
; Add packet to FIFO
|
||||||
lda #%11000000 ; ENQUEUE PACKET - transmit packet
|
lda #%11000000 ; ENQUEUE PACKET - transmit packet
|
||||||
fixup40:sta ethmmucr
|
fixup38:sta ethmmucr
|
||||||
clc
|
clc
|
||||||
rts
|
rts
|
||||||
|
|
||||||
|
|
@ -407,6 +404,14 @@ exit:
|
||||||
|
|
||||||
;---------------------------------------------------------------------
|
;---------------------------------------------------------------------
|
||||||
|
|
||||||
|
releasepacket:
|
||||||
|
; Remove and release RX packet from the FIFO
|
||||||
|
lda #%10000000
|
||||||
|
fixup39:sta ethmmucr
|
||||||
|
rts
|
||||||
|
|
||||||
|
;---------------------------------------------------------------------
|
||||||
|
|
||||||
adjustptr:
|
adjustptr:
|
||||||
lda len
|
lda len
|
||||||
ldx len+1
|
ldx len+1
|
||||||
|
|
|
||||||
Loading…
Reference in a new issue