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https://github.com/ekeeke/Genesis-Plus-GX.git
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51 lines
1.3 KiB
C
51 lines
1.3 KiB
C
/*
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basic, incomplete SSP160x (SSP1601?) interpreter
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with SVP memory controller emu
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(c) Copyright 2008, Grazvydas "notaz" Ignotas
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Free for non-commercial use.
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For commercial use, separate licencing terms must be obtained.
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Modified for Genesis Plus GX (Eke-Eke): added BIG ENDIAN support, fixed addr/code inversion
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*/
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#include "shared.h"
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svp_t *svp = NULL;
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int16 SVP_cycles = 850;
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void svp_init(void)
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{
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svp = (void *) ((char *)cart_rom + 0x200000);
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memset(svp, 0, sizeof(*svp));
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}
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void svp_reset(void)
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{
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memcpy(svp->iram_rom + 0x800, cart_rom + 0x800, 0x20000 - 0x800);
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ssp1601_reset(&svp->ssp1601);
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}
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void svp_write_dram(uint32 address, uint32 data)
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{
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*(uint16 *)(svp->dram + (address & 0x1fffe)) = data;
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if ((address == 0x30fe06) && data) svp->ssp1601.emu_status &= ~SSP_WAIT_30FE06;
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if ((address == 0x30fe08) && data) svp->ssp1601.emu_status &= ~SSP_WAIT_30FE08;
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}
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uint32 svp_read_cell_1(uint32 address)
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{
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address >>= 1;
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address = (address & 0x7001) | ((address & 0x3e) << 6) | ((address & 0xfc0) >> 5);
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return *(uint16 *)(svp->dram + (address & 0x1fffe));
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}
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uint32 svp_read_cell_2(uint32 address)
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{
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address >>= 1;
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address = (address & 0x7801) | ((address & 0x1e) << 6) | ((address & 0x7e0) >> 4);
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return *(uint16 *)(svp->dram + (address & 0x1fffe));
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}
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