mirror of https://github.com/pevans/erc-c.git
76 lines
2.2 KiB
C
76 lines
2.2 KiB
C
#ifndef _APPLE2_MEM_H_
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#define _APPLE2_MEM_H_
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#include "apple2/apple2.h"
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#include "vm_segment.h"
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/*
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* The MOS 6502 expects 64k of addressable space, but the Apple II
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* technically has 68k of memory in each bank. (Along with having both a
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* main and an auxiliary memory bank, with identical address schemes.)
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* This is handled through bank-switching; the additional memory (which
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* is accessible through $D000 - $DFFF) is actually stored in the
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* 64k-68k block at the end.
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*/
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#define APPLE2_MEMORY_SIZE 0x11000
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/*
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* Given a slot number (1-7), this will return the memory page address
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* for the site of the ROM that is associated for the peripheral that
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* would be connected there.
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*/
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#define APPLE2_PERIPHERAL_SLOT(n) \
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(0xC000 + (n << 8))
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/*
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* This is the total size of the ROM we hold devoted to peripherals. It
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* is meant to be mapped directly to the entire $C000..$CFFF space; it's
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* zero-padded for the $C0 page, and is also zero-padded in $C8..$CF;
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* the latter being reserved for expansion peripheral ROM usage, and the
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* former for the I/O soft switches that the Apple II has.
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*/
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#define APPLE2_PERIPHERAL_SIZE 0x1000
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/*
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* Peripheral ROM can only occupy a single page in memory.
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*/
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#define APPLE2_PERIPHERAL_PAGE 0x100
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/*
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* System ROM requires a full 16k; part of it is copied into several
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* pages beginning at $C800, and much more go into $D000 - $FFFF.
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*/
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#define APPLE2_SYSROM_SIZE 0x4000
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/*
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* The size of our block of ROM is 20k; 16k for internal ROM, 4k to
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* contain all of the peripheral ROM above.
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*/
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#define APPLE2_ROM_SIZE 0x5000
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/*
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* At the highest point (with the IIe extended 80 column text card), you
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* could have a whole other 64k of data in auxiliary memory. (Of which
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* only 1k was needed for 80 columns!)
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*/
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#define APPLE2_AUX_SIZE 0x10000
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/*
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* This is the base address for system / internal ROM.
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*/
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#define APPLE2_SYSROM_OFFSET 0xC000
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/*
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* This defines the base address for bank-switchable memory
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*/
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#define APPLE2_BANK_OFFSET 0xD000
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extern SEGMENT_READER(apple2_mem_zp_read);
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extern SEGMENT_WRITER(apple2_mem_zp_write);
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extern int apple2_mem_init_sys_rom(apple2 *);
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extern void apple2_mem_map(apple2 *, vm_segment *);
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extern SEGMENT_READER(apple2_mem_switch_read);
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extern SEGMENT_WRITER(apple2_mem_switch_write);
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#endif
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