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Fix DMA from byte-wide SRAM
author Michael Pavone <pavone@retrodev.com>
date Mon, 26 Jun 2017 21:13:17 -0700
parents 11ac0b511cff
children 4e5797b3935a
comparison
equal deleted inserted replaced
1419:92e7dafcc0dc 1420:975b5b7eaa77
33 #define MAX_SOUND_CYCLES 100000 33 #define MAX_SOUND_CYCLES 100000
34 34
35 uint16_t read_dma_value(uint32_t address) 35 uint16_t read_dma_value(uint32_t address)
36 { 36 {
37 genesis_context *genesis = (genesis_context *)current_system; 37 genesis_context *genesis = (genesis_context *)current_system;
38 //TODO: Figure out what happens when you try to DMA from weird adresses like IO or banked Z80 area
39 if ((address >= 0xA00000 && address < 0xB00000) || (address >= 0xC00000 && address <= 0xE00000)) {
40 return 0;
41 }
42
38 //addresses here are word addresses (i.e. bit 0 corresponds to A1), so no need to do multiply by 2 43 //addresses here are word addresses (i.e. bit 0 corresponds to A1), so no need to do multiply by 2
39 uint16_t *ptr = get_native_pointer(address*2, (void **)genesis->m68k->mem_pointers, &genesis->m68k->options->gen); 44 return read_word(address * 2, (void **)genesis->m68k->mem_pointers, &genesis->m68k->options->gen, genesis->m68k);
40 if (ptr) {
41 return *ptr;
42 }
43 //TODO: Figure out what happens when you try to DMA from weird adresses like IO or banked Z80 area
44 return 0;
45 } 45 }
46 46
47 static uint16_t get_open_bus_value(system_header *system) 47 static uint16_t get_open_bus_value(system_header *system)
48 { 48 {
49 genesis_context *genesis = (genesis_context *)system; 49 genesis_context *genesis = (genesis_context *)system;