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several IEC routines now properly preserve X/Y registers

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FeralChild64 committed 2019-07-20 15:25:43 +02:00
1 parent eb8eefff82
commit f26431b502
14 files changed
+98 -85
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STATUS.md
+6 -6
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@@ -73,18 +73,18 @@ NOTE: Even the 'DONE' routines won't support features described as missing in on
| $FF8A | RESTOR | PARTIAL | CBINV, NMINV, and USRCMD missing |
| $FF8D | VECTOR | DONE | |
| $FF90 | SETMSG | DONE | |
| $FF93 | SECOND | PARTIAL | * work in progress |
| $FF96 | TKSA | PARTIAL | should probably also do a turnaround |
| $FF93 | SECOND | DONE | |
| $FF96 | TKSA | PARTIAL | should it do a turnaround? |
| $FF99 | MEMTOP | DONE | |
| $FF9C | MEMBOT | DONE | |
| $FF9F | SCNKEY | DONE | could be better integrated with ROM |
| $FFA2 | SETTMO | NOT DONE | |
| $FFA5 | ACPTR | NOT DONE | * work in progress |
| $FFA8 | CIOUT | PARITAL | * work in progress |
| $FFA8 | CIOUT | DONE | |
| $FFAB | UNTLK | PARITAL | * work in progress |
| $FFAE | UNLSN | PARITAL | * work in progress |
| $FFB1 | LISTEN | PARTIAL | * work in progress |
| $FFB4 | TALK | PARTIAL | * work in progress |
| $FFAE | UNLSN | DONE | |
| $FFB1 | LISTEN | DONE | |
| $FFB4 | TALK | PARTIAL | should it do a turnaround? |
| $FFB7 | READST | DONE | |
| $FFBA | SETFLS | DONE | |
| $FFBD | SETNAM | DONE | |
c64/kernal/ciout.s
+1 -3
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@@ -8,7 +8,6 @@
;; CPU registers that has to be preserved (see [RG64]): .X, .Y
;;
;; XXX currently does not preserve registers, to be fixed!
ciout:
@@ -31,9 +30,8 @@ ciout_store_in_buffer:
ciout_send_byte:
;; Send previous data
lda BSOUR
clc ; don't send with EOI
jsr iec_tx_byte
inc C3PO ; iec_tx_byte sets it to 0, but we still have something to send
jmp ciout_store_in_buffer
c64/kernal/iec_return.s
+38
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@@ -0,0 +1,38 @@
;;
;; Helper routines to return with error/success
;;
;; All of them restore X/Y registers from stack,
;; they take care about Carry flag,
;; error return reeset IEC line to default state,
;; take care about .A and IOSTATUS
;;
iec_return_success:
;; BSOUR is certainly not valid anymore
lda #$00
sta C3PO
;; Restore registers
pla
tay
pla
tax
;; Report success
clc
rts
iec_return_DEVICE_NOT_FOUND:
;; Set IEC line to normal idle state
jsr iec_set_idle
;; BSOUR is certainly not valid anymore
lda #$00
sta C3PO
;; Restore registers
pla
tay
pla
tax
;; Report error
jmp kernalerror_DEVICE_NOT_FOUND
c64/kernal/iec_tx_byte.s
+10 -13
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@@ -1,11 +1,16 @@
;; Implemented based on https://www.pagetable.com/?p=1135, https://github.com/mist64/cbmbus_doc
;; Carry flag set = signal EOI
;; Expects byte to send in BSOUR; Carry flag set = signal EOI
;; Preserves .X and .Y registers
iec_tx_byte:
;; Store byte to send on the stack
;; Store .X and .Y on the stack - preserve them
txa
pha
tya
pha
;; Notify all devices that we are going to send a byte
@@ -15,10 +20,9 @@ iec_tx_byte:
;; Common part of iec_txbyte and iec_tx_common - waits for devices
;; and transmits a byte
pla
jsr iec_tx_common
;; All done - give device time to tell if they are busy by pulling DATA
;; Give device time to tell if they are busy by pulling DATA
;; They should do it within 1ms
ldx #$FF
* lda CIA2_PRA
@@ -27,15 +31,8 @@ iec_tx_byte:
bpl +
dex
bne -
bpl iec_tx_byte_error
bpl iec_return_DEVICE_NOT_FOUND
*
;; All done
clc
rts
iec_tx_byte_error:
jsr iec_set_idle
jmp kernalerror_DEVICE_NOT_FOUND
jmp iec_return_success
c64/kernal/iec_tx_command.s
+13 -11
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@@ -1,9 +1,16 @@
;; Implemented based on https://www.pagetable.com/?p=1135, https://github.com/mist64/cbmbus_doc
;; Expects command to send in BSOUR; Carry flag set = signal EOI
;; Preserves .X and .Y registers
iec_tx_command:
;; Store command to send on the stack
;; Store .X and .Y on the stack - preserve them
txa
pha
tya
pha
;; Notify all devices that we are going to send a byte
@@ -18,11 +25,8 @@ iec_tx_command:
and #BIT_CIA2_PRA_DAT_IN ; XXX try to optimize this, move to separate routine
beq +
;; No devices present on the bus, so we can immediately return with device not found
pla
jsr iec_set_idle
jmp kernalerror_DEVICE_NOT_FOUND
;; No devices present on the bus, so we can immediately return with device not found
jmp iec_return_DEVICE_NOT_FOUND
*
;; At least one device responded, but they are still allowed to stall
;; (can be busy processing something), we have to wait till they are all
@@ -35,7 +39,6 @@ iec_tx_command:
;; and transmits a byte
clc ; Carry flag set is used for EOI mark
pla
jsr iec_tx_common
;; According to https://www.pagetable.com/?p=1135 there is some complicated and dangerous
@@ -50,8 +53,7 @@ iec_tx_command:
;; to wait for the DATA being pulled, as confirmation is expected from
;; a single device only - but not sure if it's worth the trouble
jsr iec_set_idle
jmp kernalerror_DEVICE_NOT_FOUND
jmp iec_return_DEVICE_NOT_FOUND
*
;; All done
@@ -60,5 +62,5 @@ iec_tx_command:
;; jsr iec_wait20us
;; jsr iec_set_idle
clc
rts
jmp iec_return_success
c64/kernal/iec_tx_common.s
+8 -12
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@@ -3,15 +3,15 @@
;; Implemented based on https://www.pagetable.com/?p=1135, https://github.com/mist64/cbmbus_doc
;; and http://www.zimmers.net/anonftp/pub/cbm/programming/serial-bus.pdf
;; Expects byte to send in BSOUR; Carry flag set = signal EOI
iec_tx_common:
;; Timing is critical here - execute on disabled IRQs
php
sei
;; Store the byte to send on a stack
pha
;; Wait till all receivers are ready, they should all release DATA
jsr iec_wait_for_data_release
@@ -38,13 +38,14 @@ iec_tx_common:
;; Now, we can start transmission of 8 bits of data
ldx #7
pla
iec_tx_common_sendbit:
;; Is next bit 0 or 1?
lda BSOUR
lsr
pha
sta BSOUR
bcs +
;; XXX we are actually destroying BSOUR here... is it allowed?
;; Bit is 0
jsr iec_release_clk_pull_data
@@ -65,13 +66,8 @@ iec_tx_common_bit_is_sent:
;; More bits to send?
dex
bpl iec_tx_common_nextbit
pla
bpl iec_tx_common_sendbit
plp
rts ; Flow continues differently for data/command
iec_tx_common_nextbit:
pla
jmp iec_tx_common_sendbit
c64/kernal/listen.s
+2 -3
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@@ -4,16 +4,15 @@
;;
;; - [RG64] C64 Programmer's Reference Guide - page 285
;; - [CM64] Compute's Mapping the Commodore 64 - page 223
;; - https://www.pagetable.com/?p=1031, https://github.com/mist64/cbmbus_doc
;;
;; CPU registers that has to be preserved (see [RG64]): .X, .Y
;;
;; XXX currently does not preserve registers, to be fixed!
listen:
;; This trivial routine is documented in 'Compute's Mapping the Commodore 64', page 223 and
;; https://www.pagetable.com/?p=1031, , https://github.com/mist64/cbmbus_doc
and #$1F ; make sure bits encoding the command are cleared out
ora #$20
sta BSOUR
jmp iec_tx_command
c64/kernal/load.s
+5 -9
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@@ -67,22 +67,16 @@ load_send_filename:
jsr peek_under_roms
iny
;; Save Y because iec_tx_byte will corrupt it
tax
tya
pha
;; Set Carry flag on the last file name character, to mark EOI
cmp FNLEN
cpy FNLEN
clc
bne +
sec
*
txa
;; Transmit one character
sta BSOUR
jsr iec_tx_byte
pla
tay
jmp load_send_filename
load_filename_sent:
@@ -98,6 +92,7 @@ load_filename_sent:
bcs lvs_load_verify_error
lda #$60 ; open channel / data (p3) , required according to p13
sta BSOUR
jsr iec_tx_command
bcs lvs_load_verify_error
@@ -156,6 +151,7 @@ load_loop:
jsr listen
lda #$E0
sta BSOUR
jsr iec_tx_command
;; Tell drive to unlisten
c64/kernal/open.s
+1 -10
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@@ -82,12 +82,6 @@ open_iec:
;; XXX note: this is only a temporary test implementation, real 'open' does not send anything to IEC,
;; see http://www.zimmers.net/anonftp/pub/cbm/programming/serial-bus.pdf
;; Disable IRQs, since timing matters!
sei
;; Begin sending under attention
;; XXX jsr iec_assert_atn
;; Request device to talk
lda current_device_number
jsr talk
@@ -107,8 +101,5 @@ open_iec:
clc
open_iec_error:
;; Re-enable interrupts and return
;; (iec_tx_byte will have set/cleared C flag and put result code
;; in A if it was an error).
cli
;; Carry flag will be set by low-level routines
rts
c64/kernal/second.s
+2 -3
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@@ -4,16 +4,15 @@
;;
;; - [RG64] C64 Programmer's Reference Guide - page 296
;; - [CM64] Compute's Mapping the Commodore 64 - page 223/224
;; - https://www.pagetable.com/?p=1031, , https://github.com/mist64/cbmbus_doc
;;
;; CPU registers that has to be preserved (see [RG64]): .X, .Y
;;
;; XXX currently does not preserve registers, to be fixed!
second:
;; see also https://www.pagetable.com/?p=1031, , https://github.com/mist64/cbmbus_doc
and #$1F ; make sure bits encoding the command are cleared out
ora #$60
sta BSOUR
jmp iec_tx_command
c64/kernal/talk.s
+3 -4
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@@ -4,18 +4,17 @@
;;
;; - [RG64] C64 Programmer's Reference Guide - page 301/302
;; - [CM64] Compute's Mapping the Commodore 64 - page 223
;; - https://www.pagetable.com/?p=1031, https://github.com/mist64/cbmbus_doc
;;
;; CPU registers that has to be preserved (see [RG64]): .X, .Y
;;
;; XXX currently does not preserve registers, to be fixed!
;; XXX shouldn't this do a turnaround?
talk:
;; See also https://www.pagetable.com/?p=1031, https://github.com/mist64/cbmbus_doc
and #$1F ; make sure bits encoding the command are cleared out
ora #$40
sta BSOUR
jmp iec_tx_command
c64/kernal/tksa.s
+3 -3
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@@ -4,18 +4,18 @@
;;
;; - [RG64] C64 Programmer's Reference Guide - page 302
;; - [CM64] Compute's Mapping the Commodore 64 - page 224
;; - https://www.pagetable.com/?p=1031, https://github.com/mist64/cbmbus_doc
;;
;; CPU registers that has to be preserved (see [RG64]): .X, .Y
;;
;; XXX currently does not preserve registers, to be fixed!
;; XXX shouldn't this do a turnaround?
tksa:
;; See also https://www.pagetable.com/?p=1031, , https://github.com/mist64/cbmbus_doc
and #$1F ; make sure bits encoding the command are cleared out
ora #$F0
sta BSOUR
jmp iec_tx_command
c64/kernal/unlsn.s
+3 -6
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@@ -4,11 +4,11 @@
;;
;; - [RG64] C64 Programmer's Reference Guide - page 303
;; - [CM64] Compute's Mapping the Commodore 64 - page 224
;; - https://www.pagetable.com/?p=1031, , https://github.com/mist64/cbmbus_doc
;;
;; CPU registers that has to be preserved (see [RG64]): .X, .Y
;;
;; XXX currently does not preserve registers, to be fixed!
unlsn:
@@ -17,15 +17,12 @@ unlsn:
;; First check whether we have something to be sent in the buffer
lda C3PO
beq +
lda BSOUR
sec ; send it with EOI
jsr iec_tx_byte ; XXX what about the status of this operation?
;; Mark the buffer as invalid
lda #$00
sta C3PO
*
;; Buffer empty send the command
;; Buffer empty, send the command
lda #$3F
sta BSOUR
jmp iec_tx_command
c64/kernal/untlk.s
+3 -2
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@@ -4,16 +4,17 @@
;;
;; - [RG64] C64 Programmer's Reference Guide - page 304
;; - [CM64] Compute's Mapping the Commodore 64 - page 224
;; - https://www.pagetable.com/?p=1031, , https://github.com/mist64/cbmbus_doc
;;
;; CPU registers that has to be preserved (see [RG64]): .X, .Y
;;
;; XXX currently does not preserve registers, to be fixed!
;; XXX shouldn't this do a turnaround?
untlk:
;; This trivial routine is documented in 'Compute's Mapping the Commodore 64', page 224
lda #$5F
sta BSOUR
jmp iec_tx_command