sdc: add sdcPutC
Wriiiiiite!
This commit is contained in:
Virgil Dupras
parent
3bc7cec03a
commit
5e5c7e6592
160
kernel/sdc.asm
160
kernel/sdc.asm
@ -35,7 +35,6 @@
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; sector.
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.equ SDC_BUFSEC SDC_BUF+SDC_BLKSIZE
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; Whether the buffer has been written to. 0 means clean. 1 means dirty.
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; (not used yet)
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.equ SDC_BUFDIRTY SDC_BUFSEC+1
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.equ SDC_RAMEND SDC_BUFDIRTY+1
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@ -314,32 +313,119 @@ sdcReadBlk:
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pop bc
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ret
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; *** shell cmds ***
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; Write the contents of (SDC_BUF) in sector number (SDC_BUFSEC). Unsets the
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; (SDC_BUFDIRTY) flag on success.
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; A returns 0 in A on success (with Z set), non-zero (with Z unset) on error.
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sdcWriteBlk:
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ld a, (SDC_BUFDIRTY)
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or a ; cp 0
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ret z ; return success, but do nothing.
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sdcInitializeCmd:
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.db "sdci", 0, 0, 0
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call sdcInitialize
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jp sdcSetBlkSize ; return
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push bc
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push hl
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; *** blkdev routines ***
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out (SDC_PORT_CSLOW), a
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ld a, (SDC_BUFSEC)
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ld hl, 0 ; write single block at addr A
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ld d, 0
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ld e, a
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ld a, 0b01011000 ; CMD24
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call sdcCmd
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or a ; cp 0
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jr nz, .error
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sdcGetC:
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; SDC_PTR points to the character we're supposed to read right now, but
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; we first have to check whether we need to load a new sector in memory.
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; To do this, we compare the high 7 bits of (SDC_PTR) with (SDC_BUFSEC).
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; If they're different, we need to load a new block.
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; Before sending the data packet, we need to send at least one empty
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; byte.
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ld a, 0xff
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call sdcSendRecv
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; data packet token for CMD24
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ld a, 0xfe
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call sdcSendRecv
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; Sending our data token!
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ld bc, SDC_BLKSIZE
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ld hl, SDC_BUF
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.loop:
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ld a, (hl)
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call sdcSendRecv
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cpi ; a trick to inc HL and dec BC at the same time.
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; P/V indicates whether BC reached 0
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jp pe, .loop ; BC is not zero, loop
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; Send our 2 CRC bytes. They can be anything
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call sdcIdle
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call sdcIdle
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; Let's see what response we have
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call sdcWaitResp
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and 0b00011111 ; We ignore the first 3 bits of the response.
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cp 0b00000101 ; A valid response is "010" in bits 3:1 flanked
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; by 0 on its left and 1 on its right.
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jr nz, .error
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; good! Now, we need to let the card process this data. It will return
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; 0xff when it's not busy any more.
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call sdcWaitResp
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xor a
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ld (SDC_BUFDIRTY), a
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jr .end
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.error:
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; try to preserve error code
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or a ; cp 0
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jr nz, .end ; already non-zero
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inc a ; zero, adjust
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.end:
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out (SDC_PORT_CSHIGH), a
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pop hl
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pop bc
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ret
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; Ensures that (SDC_BUFSEC) is in sync with (SDC_PTR), that is, that the current
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; buffer in memory corresponds to where SDC_PTR points to. If it doesn't, loads
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; the sector that (SDC_PTR) points to in (SDC_BUF) and update (SDC_BUFSEC).
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; If the (SDC_BUFDIRTY) flag is set, we write the content of the in-memory
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; buffer to the SD card before we read a new sector.
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; Returns Z on success, not-Z on error (with the error code from either
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; sdcReadBlk or sdcWriteBlk)
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sdcSync:
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; SDC_PTR points to the character we're supposed to read or right now,
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; but we first have to check whether we need to load a new sector in
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; memory. To do this, we compare the high 7 bits of (SDC_PTR) with
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; (SDC_BUFSEC). If they're different, we need to load a new block.
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push hl
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ld a, (SDC_BUFSEC)
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ld h, a
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ld a, (SDC_PTR+1) ; high byte has bufsec in its high 7 bits
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srl a
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cp h
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jr z, .noload
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; not equal, we need to load a new sector. A already contains the
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; sector to load.
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call sdcReadBlk
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jr nz, .error
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.noload:
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pop hl
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ret z ; equal? nothing to do
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; We have to read a new sector, but first, let's write the current one
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; if needed.
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call sdcWriteBlk
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ret nz ; error
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; Let's read our new sector
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ld a, (SDC_PTR+1)
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srl a
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jp sdcReadBlk ; returns
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; *** shell cmds ***
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sdcInitializeCmd:
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.db "sdci", 0, 0, 0
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call sdcInitialize
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jp sdcSetBlkSize ; returns
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; Flush the current SDC buffer if dirty
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sdcFlushCmd:
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.db "sdcf", 0, 0, 0
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jp sdcWriteBlk ; returns
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; *** blkdev routines ***
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; Make HL point to (SDC_PTR) in current buffer
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_sdcPlaceBuf:
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call sdcSync
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ret nz ; error
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ld a, (SDC_PTR+1) ; high byte
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and 0x01 ; is first bit set?
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jr nz, .highbuf ; first bit set? we're in the "highbuf" zone.
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@ -355,7 +441,14 @@ sdcGetC:
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; all we need is to increase HL by the number in SDC_PTR's LSB (little
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; endian, remember).
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ld a, (SDC_PTR) ; LSB
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call addHL
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call addHL ; returns
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xor a ; ensure Z
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ret
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sdcGetC:
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push hl
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call _sdcPlaceBuf
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jr nz, .error
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; This is it!
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ld a, (hl)
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@ -367,13 +460,40 @@ sdcGetC:
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cp a ; ensure Z
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jr .end
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.error:
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call unsetZ
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.end:
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pop hl
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ret
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sdcPutC:
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push hl
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push af ; let's remember the char we put, _sdcPlaceBuf
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; destroys A.
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call _sdcPlaceBuf
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jr nz, .error
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; HL points to our dest. Recall A and write
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pop af
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ld (hl), a
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; we need to increase (SDC_PTR)
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ld hl, (SDC_PTR)
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inc hl
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ld (SDC_PTR), hl
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ld a, 1
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ld (SDC_BUFDIRTY), a
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xor a ; ensure Z
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jr .end
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.error:
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pop af
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call unsetZ
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.end:
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pop hl
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ret
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sdcSeek:
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ld (SDC_PTR), hl
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ret
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@ -10,10 +10,11 @@ jp init ; 3 bytes
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; *** Jump Table ***
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jp printstr
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jp fsOpen
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jp fsSeek
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jp fsTell
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jp fsGetC
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jp sdcWaitResp
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jp sdcCmd
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jp sdcCmdR1
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jp sdcCmdR7
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jp sdcSendRecv
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; interrupt hook
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.fill 0x38-$
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@ -28,7 +29,7 @@ jp aciaInt
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#include "blockdev.asm"
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; List of devices
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.dw aciaGetC, aciaPutC, 0, 0
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.dw sdcGetC, 0, sdcSeek, sdcTell
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.dw sdcGetC, sdcPutC, sdcSeek, sdcTell
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.dw blk2GetC, blk2PutC, blk2Seek, blk2Tell
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#include "blockdev_cmds.asm"
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@ -42,9 +43,9 @@ jp aciaInt
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#include "fs_cmds.asm"
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.equ SHELL_RAMSTART FS_RAMEND
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.equ SHELL_EXTRA_CMD_COUNT 8
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.equ SHELL_EXTRA_CMD_COUNT 9
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#include "shell.asm"
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.dw sdcInitializeCmd, blkBselCmd, blkSeekCmd
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.dw sdcInitializeCmd, sdcFlushCmd, blkBselCmd, blkSeekCmd
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.dw fsOnCmd, flsCmd, fnewCmd, fdelCmd, fopnCmd
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#include "pgm.asm"
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