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(MESS) geneve: Wait state behavior almost perfect. (nw)
This commit is contained in:
Michael Zapf
parent
d14e73e4fd
commit
08b2b8aed3
@ -79,20 +79,6 @@
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to detect AMD=0, AME=1. Otherwise these cards, although completely decoding the
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19-bit address, would reappear at 512 KiB distances.
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For the page numbers we get:
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Standard:
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00-3f are internal (DRAM)
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40-7f are internal expansion, never used
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80-bf are the P-Box address space (optional Memex and peripheral cards at that location)
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c0-ff are internal (SRAM, EPROM)
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Genmod:
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00-3f are the P-Box address space (expect Memex at that location)
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40-7f are the P-Box address space (expect Memex at that location)
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80-bf are the P-Box address space (expect Memex at that location)
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c0-ef are the P-Box address space (expect Memex at that location)
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f0-ff are internal (EPROM)
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Genmod's double switch box is also emulated. There are two switches:
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- Turbo mode: Activates or deactivates the wait state logic on the Geneve
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board. This switch may be changed at any time.
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@ -101,26 +87,50 @@
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triggers a reset when changed.
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===================
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Mapping
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-------
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===================
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Geneve mode
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-----------
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Video: f100 / f102 (mirror f108 / f10a) (read)
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Mapper: f110 - f117
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Keyboard: f118
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Clock: f130 - f13f
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Sound: f120
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Logical address space: 64 KiB
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TI mode
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-------
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Geneve mode:
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Video: F100, F102, F104, F106 (mirror: +8)
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Mapper: F110 - F117
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Keyboard: F118
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Clock: F130 - F13F
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Sound: F120
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TI mode:
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Video: 8800, 8802, 8804, 8806
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Mapper: 8000 - 8007
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Keyboard: 8008 - 800f
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Clock: 8010 - 801f
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Video: 8800 / 8802
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Keyboard: 8008 - 800F
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Clock: 8010 - 801F
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Speech: 9000 / 9400
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Grom: 9800 / 9802
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Physical address space: 2 MiB
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Start End Banks
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000000 - 07FFFF 00-3F 512 KiB DRAM on-board
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080000 - 0FFFFF 40-7F 512 KiB on-board expansion (never used)
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100000 - 16FFFF 80-B7 448 KiB P-Box space (special cards, like MEMEX)
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170000 - 17FFFF B8-BF 64 KiB P-Box space (current cards)
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180000 - 1DFFFF C0-EF 384 KiB SRAM space on-board; stock Geneve comes with 32 KiB
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1E0000 - 1FFFFF F0-FF 128 KiB EPROM space; 16 KiB actually used, 8 mirrors
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GenMod modification:
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TI mode
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000000 - 07FFFF 00-3F 512 KiB DRAM on-board
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080000 - 1DFFFF 40-EF 1408 KiB P-Box space
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1E0000 - 1FFFFF F0-FF 128 KiB EPROM space; 16 KiB actually used, 8 mirrors
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Non-TI mode
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000000 - 1DFFFF 00-EF 1920 KiB P-Box space
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1E0000 - 1FFFFF F0-FF 128 KiB EPROM space; 16 KiB actually used, 8 mirrors
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Waitstate handling
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------------------
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@ -137,7 +147,7 @@
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- memory-mapped devices (mapper, clock, keyboard): 1 WS
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- accesses to the peripheral expansion box: 1 WS
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- accesses to on-board DRAM: 1 WS
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- accesses to video: 14 WS
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- accesses to video: 15 WS
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- accesses to sound: ~25 WS
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- accesses to SRAM: 0 WS
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@ -155,6 +165,11 @@
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RAM. Additional wait states are requested by m_video_waitstates = true.
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Without additional wait states, the video access takes the usual 1 or 2 WS.
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Waitstate behavior (Nov 2013)
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Almost perfect. Only video read access from code in DRAM is too fast by one WS
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Michael Zapf, October 2011
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February 2012: rewritten as class, restructured
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@ -269,6 +284,11 @@ void geneve_mapper_device::set_wait(int min)
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{
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if (m_debug_no_ws) return;
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if (m_extra_waitstates && min < 2) min = 2;
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// if we still have video wait states, do not set this counter
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// (or it will assert READY when expiring)
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if (m_ext_waitcount > min) return;
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// need one more pass so that READY will be asserted again
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m_waitcount = min + 1;
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if (m_waitcount > 1)
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@ -352,7 +372,7 @@ READ8_MEMBER( geneve_mapper_device::readm )
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if (VERBOSE>7) LOG("genboard: Read video %04x -> %02x\n", dec->offset, value);
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// Video wait states are created *after* the access
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// Accordingly, they have no effect when execution is in onchip RAM
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if (m_video_waitstates) set_ext_wait(16);
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if (m_video_waitstates) set_ext_wait(15);
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break;
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case MLGMAPPER:
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@ -408,7 +428,7 @@ READ8_MEMBER( geneve_mapper_device::readm )
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m_video->readz(space, dec->offset, &value, 0xff);
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if (VERBOSE>7) LOG("genboard: Read video %04x -> %02x\n", dec->offset, value);
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// See above
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if (m_video_waitstates) set_ext_wait(16);
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if (m_video_waitstates) set_ext_wait(15);
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break;
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case MLTSPEECH:
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@ -521,7 +541,7 @@ WRITE8_MEMBER( geneve_mapper_device::writem )
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m_video->write(space, dec->offset, data, 0xff);
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if (VERBOSE>7) LOG("genboard: Write video %04x <- %02x\n", offset, data);
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// See above
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if (m_video_waitstates) set_ext_wait(16);
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if (m_video_waitstates) set_ext_wait(15);
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break;
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case MLGMAPPER:
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@ -564,7 +584,7 @@ WRITE8_MEMBER( geneve_mapper_device::writem )
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m_video->write(space, dec->offset, data, 0xff);
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if (VERBOSE>7) LOG("genboard: Write video %04x <- %02x\n", offset, data);
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// See above
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if (m_video_waitstates) set_ext_wait(16);
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if (m_video_waitstates) set_ext_wait(15);
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break;
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case MLTSPEECH:
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