minivmac4ios/Mini vMac/mnvm_core/SCSIEMDV.c

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2016-05-01 17:05:36 +00:00
/* SCSIEMDV.c Copyright (C) 2004 Philip Cummins, Paul C. Pratt You can redistribute this file and/or modify it under the terms of version 2 of the GNU General Public License as published by the Free Software Foundation. You should have received a copy of the license along with this file; see the file COPYING. This file is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the license for more details. */ /* Small Computer System Interface EMulated DeVice Emulates the SCSI found in the Mac Plus. This code adapted from "SCSI.c" in vMac by Philip Cummins. */ /* NCR5380 chip emulation by Yoav Shadmi, 1998 */ #ifndef AllFiles #include "SYSDEPNS.h" #include "ENDIANAC.h" #include "MYOSGLUE.h" #include "EMCONFIG.h" #include "GLOBGLUE.h" #endif #include "SCSIEMDV.h" #define scsiRd 0x00 #define scsiWr 0x01 #define sCDR 0x00 /* current scsi data register (r/o) */ #define sODR 0x00 /* output data register (w/o) */ #define sICR 0x02 /* initiator command register (r/w) */ #define sMR 0x04 /* mode register (r/w) */ #define sTCR 0x06 /* target command register (r/w) */ #define sCSR 0x08 /* current SCSI bus status (r/o) */ #define sSER 0x08 /* select enable register (w/o) */ #define sBSR 0x0A /* bus and status register (r/o) */ #define sDMAtx 0x0A /* start DMA send (w/o) */ #define sIDR 0x0C /* input data register (r/o) */ #define sTDMArx 0x0C /* start DMA target receive (w/o) */ #define sRESET 0x0E /* reset parity/interrupt (r/o) */ #define sIDMArx 0x0E /* start DMA initiator receive (w/o) */ #define kSCSI_Size 0x00010 LOCALVAR ui3b SCSI[kSCSI_Size]; GLOBALPROC SCSI_Reset(void) { int i; for (i = 0; i < kSCSI_Size; i++) { SCSI[i] = 0; } } LOCALPROC SCSI_BusReset(void) { SCSI[scsiRd + sCDR] = 0; SCSI[scsiWr + sODR] = 0; SCSI[scsiRd + sICR] = 0x80; SCSI[scsiWr + sICR] &= 0x80; SCSI[scsiRd + sMR] &= 0x40; SCSI[scsiWr + sMR] &= 0x40; SCSI[scsiRd + sTCR] = 0; SCSI[scsiWr + sTCR] = 0; SCSI[scsiRd + sCSR] = 0x80; SCSI[scsiWr + sSER] = 0; SCSI[scsiRd + sBSR] = 0x10; SCSI[scsiWr + sDMAtx] = 0; SCSI[scsiRd + sIDR] = 0; SCSI[scsiWr + sTDMArx] = 0; SCSI[scsiRd + sRESET] = 0; SCSI[scsiWr + sIDMArx] = 0; #if 0 SCSI[scsiRd + sODR + dackWr] = 0; SCSI[scsiWr + sIDR + dackRd] = 0; #endif /* The missing piece of the puzzle.. :) */ put_ram_word(0xb22, get_ram_word(0xb22) | 0x8000); } LOCALPROC SCSI_Check(void) { /* The arbitration select/reselect scenario [stub.. doesn't really work...] */ if ((SCSI[scsiWr + sODR] >> 7) == 1) { /* Check if the Mac tries to be an initiator */ if ((SCSI[scsiWr + sMR] & 1) == 1) { /* the Mac set arbitration in progress */ /* stub! tell the mac that there is arbitration in progress... */ SCSI[scsiRd + sICR] |= 0x40; /* ... that we didn't lose arbitration ... */ SCSI[scsiRd + sICR] &= ~ 0x20; /* ... and that there isn't a higher priority ID present... */ SCSI[scsiRd + sCDR] = 0x00; /* ... the arbitration and selection/reselection is complete. the initiator tries to connect to the SCSI device, fails and returns after timeout. */ } } /* check the chip registers, AS SET BY THE CPU */ if ((SCSI[scsiWr + sICR] >> 7) == 1) { /* Check Assert RST */ SCSI_BusReset(); } else { SCSI[scsiRd + sICR] &= ~ 0x80; SCSI[scsiRd + sCSR] &= ~ 0x80; } if ((SCSI[scsiWr + sICR] >> 2) == 1) { /* Check Assert SEL */ SCSI[scsiRd + sCSR] |= 0x02; SCSI[scsiRd + sBSR] = 0x10; } else { SCSI[scsiRd + sCSR] &= ~ 0x02; } } GLOBALFUNC ui5b SCSI_Access(ui5b Data, blnr WriteMem, CPTR addr) { if (addr < (kSCSI_Size / 2)) { addr *= 2; if (WriteMem) { SCSI[addr + 1] = Data; SCSI_Check(); } else { Data = SCSI[addr]; } } return Data; }