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comparison vdp.c @ 1994:00873afe1fe9

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Fix regressions in Monster World IV and Sonic 3D Blast caused by address latch changes
author Michael Pavone <pavone@retrodev.com>
date Thu, 18 Jun 2020 00:20:25 -0700
parents 6b9871d3d70d
children e08c489d5602
comparison
equal deleted inserted replaced
1992:8ad431312aa7 1994:00873afe1fe9
3748 //printf("DMA Fill Address: %X, New CD: %X\n", context->address, context->cd); 3748 //printf("DMA Fill Address: %X, New CD: %X\n", context->address, context->cd);
3749 } 3749 }
3750 } 3750 }
3751 } else { 3751 } else {
3752 uint8_t mode_5 = context->regs[REG_MODE_2] & BIT_MODE_5; 3752 uint8_t mode_5 = context->regs[REG_MODE_2] & BIT_MODE_5;
3753 //contrary to what's in Charles MacDonald's doc, it seems top 2 address bits are cleared
3754 //needed for the Mona in 344 Bytes demo
3755 context->address_latch = (context->address_latch & 0x1C000) | (value & 0x3FFF); 3753 context->address_latch = (context->address_latch & 0x1C000) | (value & 0x3FFF);
3756 context->cd_latch = (context->cd_latch & 0x3C) | (value >> 14); 3754 context->cd_latch = (context->cd_latch & 0x3C) | (value >> 14);
3757 if ((value & 0xC000) == 0x8000) { 3755 if ((value & 0xC000) == 0x8000) {
3758 //Register write 3756 //Register write
3759 uint8_t reg = (value >> 8) & 0x1F; 3757 uint8_t reg = (value >> 8) & 0x1F;
3779 } 3777 }
3780 if (reg == REG_MODE_1 || reg == REG_MODE_2 || reg == REG_MODE_4) { 3778 if (reg == REG_MODE_1 || reg == REG_MODE_2 || reg == REG_MODE_4) {
3781 update_video_params(context); 3779 update_video_params(context);
3782 } 3780 }
3783 } 3781 }
3782 // The fact that this is needed seems to pour some cold water on my theory
3783 // about how the address latch actually works. Needs more search to definitively confirm
3784 clear_pending(context);
3785 context->flags &= ~FLAG_READ_FETCHED;
3786 context->flags2 &= ~FLAG2_READ_PENDING;
3784 } else if (mode_5) { 3787 } else if (mode_5) {
3785 context->flags |= FLAG_PENDING; 3788 context->flags |= FLAG_PENDING;
3786 //Should these be taken care of here or after the second write? 3789 //Should these be taken care of here or after the second write?
3787 //context->flags &= ~FLAG_READ_FETCHED; 3790 //context->flags &= ~FLAG_READ_FETCHED;
3788 //context->flags2 &= ~FLAG2_READ_PENDING; 3791 //context->flags2 &= ~FLAG2_READ_PENDING;