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viacuda: properly initialize VIA registers.

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This commit is contained in:
Maxim Poliakovski 2021-10-18 16:37:18 +02:00
parent 46549d68a2
commit f194887d34
1 changed files with 17 additions and 7 deletions
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24
devices/viacuda.cpp
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@ -1,6 +1,6 @@
/*
DingusPPC - The Experimental PowerPC Macintosh emulator
Copyright (C) 2018-20 divingkatae and maximum
Copyright (C) 2018-21 divingkatae and maximum
(theweirdo) spatium
(Contact divingkatae#1017 or powermax#2286 on Discord for more info)
@ -36,14 +36,24 @@ using namespace std;
ViaCuda::ViaCuda() {
this->name = "ViaCuda";
/* FIXME: is this the correct
VIA initialization? */
this->via_regs[VIA_A] = 0x80;
this->via_regs[VIA_DIRB] = 0xFF;
this->via_regs[VIA_DIRA] = 0xFF;
// VIA reset clears all internal registers to logic 0
// except timers/counters and the shift register
// as stated in the 6522 datasheet
this->via_regs[VIA_A] = 0;
this->via_regs[VIA_B] = 0;
this->via_regs[VIA_DIRB] = 0;
this->via_regs[VIA_DIRA] = 0;
this->via_regs[VIA_IER] = 0;
this->via_regs[VIA_ACR] = 0;
this->via_regs[VIA_PCR] = 0;
this->via_regs[VIA_IFR] = 0;
// load maximum value into the timer registers for safety
// (not prescribed in the 6522 datasheet)
this->via_regs[VIA_T1LL] = 0xFF;
this->via_regs[VIA_T1LH] = 0xFF;
this->via_regs[VIA_IER] = 0x7F;
this->via_regs[VIA_T2CL] = 0xFF;
this->via_regs[VIA_T2CH] = 0xFF;
// PRAM is part of Cuda
this->pram_obj = std::unique_ptr<NVram> (new NVram("pram.bin", 256));