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131 lines
3.6 KiB
C
131 lines
3.6 KiB
C
/*
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* apple2.mem.c
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*/
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#include "apple2.bank.h"
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#include "apple2.dbuf.h"
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#include "apple2.h"
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#include "apple2.mem.h"
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#include "objstore.h"
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/*
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* Set the memory map functions for main memory in an apple2 machine
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*/
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void
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apple2_mem_map(apple2 *mach, vm_segment *segment)
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{
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size_t addr;
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vm_segment_set_map_machine(mach);
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// Set up all of the bank-switch-related mapping. Well--almost all
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// of it.
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apple2_bank_map(segment);
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// Here we handle the 80STORE bit for our display buffers.
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apple2_dbuf_map(segment);
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// We will do the mapping for the zero page and stack addresses.
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// Accessing those addresses can be affected by bank-switching, but
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// those addresses do not actually exist in the capital
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// Bank-Switching address space.
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for (addr = 0x0; addr < 0x200; addr++) {
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vm_segment_read_map(segment, addr, apple2_mem_zp_read);
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vm_segment_write_map(segment, addr, apple2_mem_zp_write);
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}
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}
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/*
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* Initialize the peripheral ROM ($C100 - $C7FF).
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*/
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int
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apple2_mem_init_peripheral_rom(apple2 *mach)
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{
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int err;
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// Let's copy beginning at the 1-slot offset in memory, but going
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// all the way as far as the length of all peripheral ROM in memory.
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err = vm_segment_copy_buf(mach->main,
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objstore_apple2_peripheral_rom(),
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APPLE2_PERIPHERAL_SLOT(1), 0,
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APPLE2_PERIPHERAL_SIZE);
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if (err != OK) {
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log_critical("Could not copy apple2 peripheral rom");
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return ERR_BADFILE;
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}
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return OK;
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}
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/*
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* I'm still a bit hazy on how this _should_ work, but this function
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* will copy as much as we can from the system rom into both main memory
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* and into the rom segment.
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*/
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int
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apple2_mem_init_sys_rom(apple2 *mach)
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{
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int err;
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const vm_8bit *sysrom;
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const vm_8bit *prom;
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sysrom = objstore_apple2_sys_rom();
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prom = objstore_apple2_peripheral_rom();
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err = vm_segment_copy_buf(mach->rom, sysrom,
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0, 0, APPLE2_SYSROM_SIZE);
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if (err != OK) {
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log_critical("Could not copy apple2 system rom");
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return ERR_BADFILE;
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}
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err = vm_segment_copy_buf(mach->rom, prom,
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APPLE2_SYSROM_SIZE, 0,
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APPLE2_PERIPHERAL_SIZE);
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if (err != OK) {
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log_critical("Could not copy apple2 peripheral rom");
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return ERR_BADFILE;
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}
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return OK;
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}
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/*
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* This is a wrapper for reads in the zero and stack pages; if
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* BANK_ALTZP is high, then we need to use aux memory regardless of the
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* segment passed into the function. Otherwise, we need to use main
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* memory--again, regardless of the passed-in segment.
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*/
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SEGMENT_READER(apple2_mem_zp_read)
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{
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apple2 *mach = (apple2 *)_mach;
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// This is another case (see apple2.bank.c) where we don't care the
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// originating segment was; we only care whether BANK_ALTZP is on or
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// not. Like bank-switchable addresses, if it is on, then we should
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// be referencing aux memory; if not, main memory.
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segment = (mach->bank_switch & BANK_ALTZP)
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? mach->aux
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: mach->main;
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return segment->memory[addr];
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}
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/*
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* This write function will intercept writes to the zero page and the
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* stack page; primarily as a wrapper to handle the BANK_ALTZP bit in
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* the bank_switch field of the apple2 struct.
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*/
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SEGMENT_WRITER(apple2_mem_zp_write)
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{
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apple2 *mach = (apple2 *)_mach;
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// See the zp_read function for further details; the same logic
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// applies here.
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segment = (mach->bank_switch & BANK_ALTZP)
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? mach->aux
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: mach->main;
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segment->memory[addr] = value;
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}
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