Mercurial > repos > blastem
diff vdp.c @ 981:902c53d9c16f
Half assed, prefetch based open bus value emulation. Gets BlastEm up to 119/122 in VDP FIFO Testing
author | Michael Pavone <pavone@retrodev.com> |
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date | Sun, 24 Apr 2016 02:19:48 -0700 |
parents | 928442068afe |
children | 14d2f3b0e45d |
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--- a/vdp.c Sun Apr 24 01:24:38 2016 -0700 +++ b/vdp.c Sun Apr 24 02:19:48 2016 -0700 @@ -1694,9 +1694,8 @@ uint16_t vdp_control_port_read(vdp_context * context) { context->flags &= ~FLAG_PENDING; - //TODO: Open bus emulation //Bits 15-10 are not fixed like Charles MacDonald's doc suggests, but instead open bus values that reflect 68K prefetch - uint16_t value = 0; + uint16_t value = get_open_bus_value() & 0xFC00; if (context->fifo_read < 0) { value |= 0x200; }