| /* |
| * GUSEMU32 - bus interface part |
| * |
| * Copyright (C) 2000-2007 Tibor "TS" Schütz |
| * |
| * Permission is hereby granted, free of charge, to any person obtaining a copy |
| * of this software and associated documentation files (the "Software"), to deal |
| * in the Software without restriction, including without limitation the rights |
| * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell |
| * copies of the Software, and to permit persons to whom the Software is |
| * furnished to do so, subject to the following conditions: |
| * |
| * The above copyright notice and this permission notice shall be included in |
| * all copies or substantial portions of the Software. |
| * |
| * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
| * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
| * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL |
| * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
| * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, |
| * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN |
| * THE SOFTWARE. |
| */ |
| |
| /* |
| * TODO: check mixer: see 7.20 of sdk for panning pos (applies to all gus models?)? |
| */ |
| |
| #include "hw/gustate.h" |
| #include "hw/gusemu.h" |
| |
| #define GUSregb(position) (* (gusptr+(position))) |
| #define GUSregw(position) (*(GUSword *) (gusptr+(position))) |
| #define GUSregd(position) (*(GUSdword *)(gusptr+(position))) |
| |
| /* size given in bytes */ |
| unsigned int gus_read(GUSEmuState * state, int port, int size) |
| { |
| int value_read = 0; |
| |
| GUSbyte *gusptr; |
| gusptr = state->gusdatapos; |
| GUSregd(portaccesses)++; |
| |
| switch (port & 0xff0f) |
| { |
| /* MixerCtrlReg (read not supported on GUS classic) */ |
| /* case 0x200: return GUSregb(MixerCtrlReg2x0); */ |
| case 0x206: /* IRQstatReg / SB2x6IRQ */ |
| /* adlib/sb bits set in port handlers */ |
| /* timer/voice bits set in gus_irqgen() */ |
| /* dma bit set in gus_dma_transferdata */ |
| /* midi not implemented yet */ |
| return GUSregb(IRQStatReg2x6); |
| /* case 0x308: */ /* AdLib388 */ |
| case 0x208: |
| if (GUSregb(GUS45TimerCtrl) & 1) |
| return GUSregb(TimerStatus2x8); |
| return GUSregb(AdLibStatus2x8); /* AdLibStatus */ |
| case 0x309: /* AdLib389 */ |
| case 0x209: |
| return GUSregb(AdLibData2x9); /* AdLibData */ |
| case 0x20A: |
| return GUSregb(AdLibCommand2xA); /* AdLib2x8_2xA */ |
| |
| #if 0 |
| case 0x20B: /* GUS hidden registers (read not supported on GUS classic) */ |
| switch (GUSregb(RegCtrl_2xF) & 0x07) |
| { |
| case 0: /* IRQ/DMA select */ |
| if (GUSregb(MixerCtrlReg2x0) & 0x40) |
| return GUSregb(IRQ_2xB); /* control register select bit */ |
| else |
| return GUSregb(DMA_2xB); |
| /* case 1-5: */ /* general purpose emulation regs */ |
| /* return ... */ /* + status reset reg (write only) */ |
| case 6: |
| return GUSregb(Jumper_2xB); /* Joystick/MIDI enable (JumperReg) */ |
| default:; |
| } |
| break; |
| #endif |
| |
| case 0x20C: /* SB2xCd */ |
| value_read = GUSregb(SB2xCd); |
| if (GUSregb(StatRead_2xF) & 0x20) |
| GUSregb(SB2xCd) ^= 0x80; /* toggle MSB on read */ |
| return value_read; |
| /* case 0x20D: */ /* SB2xD is write only -> 2xE writes to it*/ |
| case 0x20E: |
| if (GUSregb(RegCtrl_2xF) & 0x80) /* 2xE read IRQ enabled? */ |
| { |
| GUSregb(StatRead_2xF) |= 0x80; |
| GUS_irqrequest(state, state->gusirq, 1); |
| } |
| return GUSregb(SB2xE); /* SB2xE */ |
| case 0x20F: /* StatRead_2xF */ |
| /*set/clear fixed bits */ |
| /*value_read = (GUSregb(StatRead_2xF) & 0xf9)|1; */ /*(LSB not set on GUS classic!)*/ |
| value_read = (GUSregb(StatRead_2xF) & 0xf9); |
| if (GUSregb(MixerCtrlReg2x0) & 0x08) |
| value_read |= 2; /* DMA/IRQ enabled flag */ |
| return value_read; |
| /* case 0x300: */ /* MIDI (not implemented) */ |
| /* case 0x301: */ /* MIDI (not implemented) */ |
| case 0x302: |
| return GUSregb(VoiceSelReg3x2); /* VoiceSelReg */ |
| case 0x303: |
| return GUSregb(FunkSelReg3x3); /* FunkSelReg */ |
| case 0x304: /* DataRegLoByte3x4 + DataRegWord3x4 */ |
| case 0x305: /* DataRegHiByte3x5 */ |
| switch (GUSregb(FunkSelReg3x3)) |
| { |
| /* common functions */ |
| case 0x41: /* DramDMAContrReg */ |
| value_read = GUSregb(GUS41DMACtrl); /* &0xfb */ |
| GUSregb(GUS41DMACtrl) &= 0xbb; |
| if (state->gusdma >= 4) |
| value_read |= 0x04; |
| if (GUSregb(IRQStatReg2x6) & 0x80) |
| { |
| value_read |= 0x40; |
| GUSregb(IRQStatReg2x6) &= 0x7f; |
| if (!GUSregb(IRQStatReg2x6)) |
| GUS_irqclear(state, state->gusirq); |
| } |
| return (GUSbyte) value_read; |
| /* DramDMAmemPosReg */ |
| /* case 0x42: value_read=GUSregw(GUS42DMAStart); break;*/ |
| /* 43h+44h write only */ |
| case 0x45: |
| return GUSregb(GUS45TimerCtrl); /* TimerCtrlReg */ |
| /* 46h+47h write only */ |
| /* 48h: samp freq - write only */ |
| case 0x49: |
| return GUSregb(GUS49SampCtrl) & 0xbf; /* SampCtrlReg */ |
| /* case 4bh: */ /* joystick trim not supported */ |
| /* case 0x4c: return GUSregb(GUS4cReset); */ /* GUSreset: write only*/ |
| /* voice specific functions */ |
| case 0x80: |
| case 0x81: |
| case 0x82: |
| case 0x83: |
| case 0x84: |
| case 0x85: |
| case 0x86: |
| case 0x87: |
| case 0x88: |
| case 0x89: |
| case 0x8a: |
| case 0x8b: |
| case 0x8c: |
| case 0x8d: |
| { |
| int offset = 2 * (GUSregb(FunkSelReg3x3) & 0x0f); |
| offset += ((int) GUSregb(VoiceSelReg3x2) & 0x1f) << 5; /* = Voice*32 + Funktion*2 */ |
| value_read = GUSregw(offset); |
| } |
| break; |
| /* voice unspecific functions */ |
| case 0x8e: /* NumVoice */ |
| return GUSregb(NumVoices); |
| case 0x8f: /* irqstatreg */ |
| /* (pseudo IRQ-FIFO is processed during a gus_write(0x3X3,0x8f)) */ |
| return GUSregb(SynVoiceIRQ8f); |
| default: |
| return 0xffff; |
| } |
| if (size == 1) |
| { |
| if ((port & 0xff0f) == 0x305) |
| value_read = value_read >> 8; |
| value_read &= 0xff; |
| } |
| return (GUSword) value_read; |
| /* case 0x306: */ /* Mixer/Version info */ |
| /* return 0xff; */ /* Pre 3.6 boards, ICS mixer NOT present */ |
| case 0x307: /* DRAMaccess */ |
| { |
| GUSbyte *adr; |
| adr = state->himemaddr + (GUSregd(GUSDRAMPOS24bit) & 0xfffff); |
| return *adr; |
| } |
| default:; |
| } |
| return 0xffff; |
| } |
| |
| void gus_write(GUSEmuState * state, int port, int size, unsigned int data) |
| { |
| GUSbyte *gusptr; |
| gusptr = state->gusdatapos; |
| GUSregd(portaccesses)++; |
| |
| switch (port & 0xff0f) |
| { |
| case 0x200: /* MixerCtrlReg */ |
| GUSregb(MixerCtrlReg2x0) = (GUSbyte) data; |
| break; |
| case 0x206: /* IRQstatReg / SB2x6IRQ */ |
| if (GUSregb(GUS45TimerCtrl) & 0x20) /* SB IRQ enabled? -> set 2x6IRQ bit */ |
| { |
| GUSregb(TimerStatus2x8) |= 0x08; |
| GUSregb(IRQStatReg2x6) = 0x10; |
| GUS_irqrequest(state, state->gusirq, 1); |
| } |
| break; |
| case 0x308: /* AdLib 388h */ |
| case 0x208: /* AdLibCommandReg */ |
| GUSregb(AdLibCommand2xA) = (GUSbyte) data; |
| break; |
| case 0x309: /* AdLib 389h */ |
| case 0x209: /* AdLibDataReg */ |
| if ((GUSregb(AdLibCommand2xA) == 0x04) && (!(GUSregb(GUS45TimerCtrl) & 1))) /* GUS auto timer mode enabled? */ |
| { |
| if (data & 0x80) |
| GUSregb(TimerStatus2x8) &= 0x1f; /* AdLib IRQ reset? -> clear maskable adl. timer int regs */ |
| else |
| GUSregb(TimerDataReg2x9) = (GUSbyte) data; |
| } |
| else |
| { |
| GUSregb(AdLibData2x9) = (GUSbyte) data; |
| if (GUSregb(GUS45TimerCtrl) & 0x02) |
| { |
| GUSregb(TimerStatus2x8) |= 0x01; |
| GUSregb(IRQStatReg2x6) = 0x10; |
| GUS_irqrequest(state, state->gusirq, 1); |
| } |
| } |
| break; |
| case 0x20A: |
| GUSregb(AdLibStatus2x8) = (GUSbyte) data; |
| break; /* AdLibStatus2x8 */ |
| case 0x20B: /* GUS hidden registers */ |
| switch (GUSregb(RegCtrl_2xF) & 0x7) |
| { |
| case 0: |
| if (GUSregb(MixerCtrlReg2x0) & 0x40) |
| GUSregb(IRQ_2xB) = (GUSbyte) data; /* control register select bit */ |
| else |
| GUSregb(DMA_2xB) = (GUSbyte) data; |
| break; |
| /* case 1-4: general purpose emulation regs */ |
| case 5: /* clear stat reg 2xF */ |
| GUSregb(StatRead_2xF) = 0; /* ToDo: is this identical with GUS classic? */ |
| if (!GUSregb(IRQStatReg2x6)) |
| GUS_irqclear(state, state->gusirq); |
| break; |
| case 6: /* Jumper reg (Joystick/MIDI enable) */ |
| GUSregb(Jumper_2xB) = (GUSbyte) data; |
| break; |
| default:; |
| } |
| break; |
| case 0x20C: /* SB2xCd */ |
| if (GUSregb(GUS45TimerCtrl) & 0x20) |
| { |
| GUSregb(TimerStatus2x8) |= 0x10; /* SB IRQ enabled? -> set 2xCIRQ bit */ |
| GUSregb(IRQStatReg2x6) = 0x10; |
| GUS_irqrequest(state, state->gusirq, 1); |
| } |
| case 0x20D: /* SB2xCd no IRQ */ |
| GUSregb(SB2xCd) = (GUSbyte) data; |
| break; |
| case 0x20E: /* SB2xE */ |
| GUSregb(SB2xE) = (GUSbyte) data; |
| break; |
| case 0x20F: |
| GUSregb(RegCtrl_2xF) = (GUSbyte) data; |
| break; /* CtrlReg2xF */ |
| case 0x302: /* VoiceSelReg */ |
| GUSregb(VoiceSelReg3x2) = (GUSbyte) data; |
| break; |
| case 0x303: /* FunkSelReg */ |
| GUSregb(FunkSelReg3x3) = (GUSbyte) data; |
| if ((GUSbyte) data == 0x8f) /* set irqstatreg, get voicereg and clear IRQ */ |
| { |
| int voice; |
| if (GUSregd(voicewavetableirq)) /* WavetableIRQ */ |
| { |
| for (voice = 0; voice < 31; voice++) |
| { |
| if (GUSregd(voicewavetableirq) & (1 << voice)) |
| { |
| GUSregd(voicewavetableirq) ^= (1 << voice); /* clear IRQ bit */ |
| GUSregb(voice << 5) &= 0x7f; /* clear voice reg irq bit */ |
| if (!GUSregd(voicewavetableirq)) |
| GUSregb(IRQStatReg2x6) &= 0xdf; |
| if (!GUSregb(IRQStatReg2x6)) |
| GUS_irqclear(state, state->gusirq); |
| GUSregb(SynVoiceIRQ8f) = voice | 0x60; /* (bit==0 => IRQ wartend) */ |
| return; |
| } |
| } |
| } |
| else if (GUSregd(voicevolrampirq)) /* VolRamp IRQ */ |
| { |
| for (voice = 0; voice < 31; voice++) |
| { |
| if (GUSregd(voicevolrampirq) & (1 << voice)) |
| { |
| GUSregd(voicevolrampirq) ^= (1 << voice); /* clear IRQ bit */ |
| GUSregb((voice << 5) + VSRVolRampControl) &= 0x7f; /* clear voice volume reg irq bit */ |
| if (!GUSregd(voicevolrampirq)) |
| GUSregb(IRQStatReg2x6) &= 0xbf; |
| if (!GUSregb(IRQStatReg2x6)) |
| GUS_irqclear(state, state->gusirq); |
| GUSregb(SynVoiceIRQ8f) = voice | 0x80; /* (bit==0 => IRQ wartend) */ |
| return; |
| } |
| } |
| } |
| GUSregb(SynVoiceIRQ8f) = 0xe8; /* kein IRQ wartet */ |
| } |
| break; |
| case 0x304: |
| case 0x305: |
| { |
| GUSword writedata = (GUSword) data; |
| GUSword readmask = 0x0000; |
| if (size == 1) |
| { |
| readmask = 0xff00; |
| writedata &= 0xff; |
| if ((port & 0xff0f) == 0x305) |
| { |
| writedata = (GUSword) (writedata << 8); |
| readmask = 0x00ff; |
| } |
| } |
| switch (GUSregb(FunkSelReg3x3)) |
| { |
| /* voice specific functions */ |
| case 0x00: |
| case 0x01: |
| case 0x02: |
| case 0x03: |
| case 0x04: |
| case 0x05: |
| case 0x06: |
| case 0x07: |
| case 0x08: |
| case 0x09: |
| case 0x0a: |
| case 0x0b: |
| case 0x0c: |
| case 0x0d: |
| { |
| int offset; |
| if (!(GUSregb(GUS4cReset) & 0x01)) |
| break; /* reset flag active? */ |
| offset = 2 * (GUSregb(FunkSelReg3x3) & 0x0f); |
| offset += (GUSregb(VoiceSelReg3x2) & 0x1f) << 5; /* = Voice*32 + Funktion*2 */ |
| GUSregw(offset) = (GUSword) ((GUSregw(offset) & readmask) | writedata); |
| } |
| break; |
| /* voice unspecific functions */ |
| case 0x0e: /* NumVoices */ |
| GUSregb(NumVoices) = (GUSbyte) data; |
| break; |
| /* case 0x0f: */ /* read only */ |
| /* common functions */ |
| case 0x41: /* DramDMAContrReg */ |
| GUSregb(GUS41DMACtrl) = (GUSbyte) data; |
| if (data & 0x01) |
| GUS_dmarequest(state); |
| break; |
| case 0x42: /* DramDMAmemPosReg */ |
| GUSregw(GUS42DMAStart) = (GUSregw(GUS42DMAStart) & readmask) | writedata; |
| GUSregb(GUS50DMAHigh) &= 0xf; /* compatibility stuff... */ |
| break; |
| case 0x43: /* DRAMaddrLo */ |
| GUSregd(GUSDRAMPOS24bit) = |
| (GUSregd(GUSDRAMPOS24bit) & (readmask | 0xff0000)) | writedata; |
| break; |
| case 0x44: /* DRAMaddrHi */ |
| GUSregd(GUSDRAMPOS24bit) = |
| (GUSregd(GUSDRAMPOS24bit) & 0xffff) | ((data & 0x0f) << 16); |
| break; |
| case 0x45: /* TCtrlReg */ |
| GUSregb(GUS45TimerCtrl) = (GUSbyte) data; |
| if (!(data & 0x20)) |
| GUSregb(TimerStatus2x8) &= 0xe7; /* sb IRQ dis? -> clear 2x8/2xC sb IRQ flags */ |
| if (!(data & 0x02)) |
| GUSregb(TimerStatus2x8) &= 0xfe; /* adlib data IRQ dis? -> clear 2x8 adlib IRQ flag */ |
| if (!(GUSregb(TimerStatus2x8) & 0x19)) |
| GUSregb(IRQStatReg2x6) &= 0xef; /* 0xe6; $$clear IRQ if both IRQ bits are inactive or cleared */ |
| /* catch up delayed timer IRQs: */ |
| if ((GUSregw(TimerIRQs) > 1) && (GUSregb(TimerDataReg2x9) & 3)) |
| { |
| if (GUSregb(TimerDataReg2x9) & 1) /* start timer 1 (80us decrement rate) */ |
| { |
| if (!(GUSregb(TimerDataReg2x9) & 0x40)) |
| GUSregb(TimerStatus2x8) |= 0xc0; /* maskable bits */ |
| if (data & 4) /* timer1 irq enable */ |
| { |
| GUSregb(TimerStatus2x8) |= 4; /* nonmaskable bit */ |
| GUSregb(IRQStatReg2x6) |= 4; /* timer 1 irq pending */ |
| } |
| } |
| if (GUSregb(TimerDataReg2x9) & 2) /* start timer 2 (320us decrement rate) */ |
| { |
| if (!(GUSregb(TimerDataReg2x9) & 0x20)) |
| GUSregb(TimerStatus2x8) |= 0xa0; /* maskable bits */ |
| if (data & 8) /* timer2 irq enable */ |
| { |
| GUSregb(TimerStatus2x8) |= 2; /* nonmaskable bit */ |
| GUSregb(IRQStatReg2x6) |= 8; /* timer 2 irq pending */ |
| } |
| } |
| GUSregw(TimerIRQs)--; |
| if (GUSregw(BusyTimerIRQs) > 1) |
| GUSregw(BusyTimerIRQs)--; |
| else |
| GUSregw(BusyTimerIRQs) = |
| GUS_irqrequest(state, state->gusirq, GUSregw(TimerIRQs)); |
| } |
| else |
| GUSregw(TimerIRQs) = 0; |
| |
| if (!(data & 0x04)) |
| { |
| GUSregb(TimerStatus2x8) &= 0xfb; /* clear non-maskable timer1 bit */ |
| GUSregb(IRQStatReg2x6) &= 0xfb; |
| } |
| if (!(data & 0x08)) |
| { |
| GUSregb(TimerStatus2x8) &= 0xfd; /* clear non-maskable timer2 bit */ |
| GUSregb(IRQStatReg2x6) &= 0xf7; |
| } |
| if (!GUSregb(IRQStatReg2x6)) |
| GUS_irqclear(state, state->gusirq); |
| break; |
| case 0x46: /* Counter1 */ |
| GUSregb(GUS46Counter1) = (GUSbyte) data; |
| break; |
| case 0x47: /* Counter2 */ |
| GUSregb(GUS47Counter2) = (GUSbyte) data; |
| break; |
| /* case 0x48: */ /* sampling freq reg not emulated (same as interwave) */ |
| case 0x49: /* SampCtrlReg */ |
| GUSregb(GUS49SampCtrl) = (GUSbyte) data; |
| break; |
| /* case 0x4b: */ /* joystick trim not emulated */ |
| case 0x4c: /* GUSreset */ |
| GUSregb(GUS4cReset) = (GUSbyte) data; |
| if (!(GUSregb(GUS4cReset) & 1)) /* reset... */ |
| { |
| GUSregd(voicewavetableirq) = 0; |
| GUSregd(voicevolrampirq) = 0; |
| GUSregw(TimerIRQs) = 0; |
| GUSregw(BusyTimerIRQs) = 0; |
| GUSregb(NumVoices) = 0xcd; |
| GUSregb(IRQStatReg2x6) = 0; |
| GUSregb(TimerStatus2x8) = 0; |
| GUSregb(AdLibData2x9) = 0; |
| GUSregb(TimerDataReg2x9) = 0; |
| GUSregb(GUS41DMACtrl) = 0; |
| GUSregb(GUS45TimerCtrl) = 0; |
| GUSregb(GUS49SampCtrl) = 0; |
| GUSregb(GUS4cReset) &= 0xf9; /* clear IRQ and DAC enable bits */ |
| GUS_irqclear(state, state->gusirq); |
| } |
| /* IRQ enable bit checked elsewhere */ |
| /* EnableDAC bit may be used by external callers */ |
| break; |
| } |
| } |
| break; |
| case 0x307: /* DRAMaccess */ |
| { |
| GUSbyte *adr; |
| adr = state->himemaddr + (GUSregd(GUSDRAMPOS24bit) & 0xfffff); |
| *adr = (GUSbyte) data; |
| } |
| break; |
| } |
| } |
| |
| /* Attention when breaking up a single DMA transfer to multiple ones: |
| * it may lead to multiple terminal count interrupts and broken transfers: |
| * |
| * 1. Whenever you transfer a piece of data, the gusemu callback is invoked |
| * 2. The callback may generate a TC irq (if the register was set up to do so) |
| * 3. The irq may result in the program using the GUS to reprogram the GUS |
| * |
| * Some programs also decide to upload by just checking if TC occurs |
| * (via interrupt or a cleared GUS dma flag) |
| * and then start the next transfer, without checking DMA state |
| * |
| * Thus: Always make sure to set the TC flag correctly! |
| * |
| * Note that the genuine GUS had a granularity of 16 bytes/words for low/high DMA |
| * while later cards had atomic granularity provided by an additional GUS50DMAHigh register |
| * GUSemu also uses this register to support byte-granular transfers for better compatibility |
| * with emulators other than GUSemu32 |
| */ |
| |
| void gus_dma_transferdata(GUSEmuState * state, char *dma_addr, unsigned int count, int TC) |
| { |
| /* this function gets called by the callback function as soon as a DMA transfer is about to start |
| * dma_addr is a translated address within accessible memory, not the physical one, |
| * count is (real dma count register)+1 |
| * note that the amount of bytes transferred is fully determined by values in the DMA registers |
| * do not forget to update DMA states after transferring the entire block: |
| * DREQ cleared & TC asserted after the _whole_ transfer */ |
| |
| char *srcaddr; |
| char *destaddr; |
| char msbmask = 0; |
| GUSbyte *gusptr; |
| gusptr = state->gusdatapos; |
| |
| srcaddr = dma_addr; /* system memory address */ |
| { |
| int offset = (GUSregw(GUS42DMAStart) << 4) + (GUSregb(GUS50DMAHigh) & 0xf); |
| if (state->gusdma >= 4) |
| offset = (offset & 0xc0000) + (2 * (offset & 0x1fff0)); /* 16 bit address translation */ |
| destaddr = (char *) state->himemaddr + offset; /* wavetable RAM address */ |
| } |
| |
| GUSregw(GUS42DMAStart) += (GUSword) (count >> 4); /* ToDo: add 16bit GUS page limit? */ |
| GUSregb(GUS50DMAHigh) = (GUSbyte) ((count + GUSregb(GUS50DMAHigh)) & 0xf); /* ToDo: add 16bit GUS page limit? */ |
| |
| if (GUSregb(GUS41DMACtrl) & 0x02) /* direction, 0 := sysram->gusram */ |
| { |
| char *tmpaddr = destaddr; |
| destaddr = srcaddr; |
| srcaddr = tmpaddr; |
| } |
| |
| if ((GUSregb(GUS41DMACtrl) & 0x80) && (!(GUSregb(GUS41DMACtrl) & 0x02))) |
| msbmask = (const char) 0x80; /* invert MSB */ |
| for (; count > 0; count--) |
| { |
| if (GUSregb(GUS41DMACtrl) & 0x40) |
| *(destaddr++) = *(srcaddr++); /* 16 bit lobyte */ |
| else |
| *(destaddr++) = (msbmask ^ (*(srcaddr++))); /* 8 bit */ |
| if (state->gusdma >= 4) |
| *(destaddr++) = (msbmask ^ (*(srcaddr++))); /* 16 bit hibyte */ |
| } |
| |
| if (TC) |
| { |
| (GUSregb(GUS41DMACtrl)) &= 0xfe; /* clear DMA request bit */ |
| if (GUSregb(GUS41DMACtrl) & 0x20) /* DMA terminal count IRQ */ |
| { |
| GUSregb(IRQStatReg2x6) |= 0x80; |
| GUS_irqrequest(state, state->gusirq, 1); |
| } |
| } |
| } |
