13cbade08a
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@30397 a1c6a512-1295-4272-9138-f99709370657
132 lines
3.4 KiB
C
132 lines
3.4 KiB
C
// PC Engine CPU emulator for use with HES music files
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// Game_Music_Emu 0.6-pre
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#ifndef HES_CPU_H
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#define HES_CPU_H
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#include "blargg_common.h"
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#include "blargg_source.h"
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typedef int hes_time_t; // clock cycle count
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typedef int hes_addr_t; // 16-bit address
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struct Hes_Emu;
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enum { future_time = INT_MAX/2 + 1 };
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enum { page_bits = 13 };
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enum { page_size = 1 << page_bits };
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enum { page_count = 0x10000 / page_size };
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// Can read this many bytes past end of a page
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enum { cpu_padding = 8 };
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enum { irq_inhibit_mask = 0x04 };
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enum { idle_addr = 0x1FFF };
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// Cpu state
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struct cpu_state_t {
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byte const* code_map [page_count + 1];
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hes_time_t base;
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int time;
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};
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// NOT kept updated during emulation.
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struct registers_t {
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uint16_t pc;
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byte a;
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byte x;
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byte y;
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byte flags;
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byte sp;
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};
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struct Hes_Cpu {
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struct registers_t r;
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hes_time_t irq_time_;
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hes_time_t end_time_;
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struct cpu_state_t* cpu_state; // points to state_ or a local copy within run()
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struct cpu_state_t cpu_state_;
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// page mapping registers
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uint8_t mmr [page_count + 1];
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uint8_t ram [page_size];
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};
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// Init cpu state
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static inline void Cpu_init( struct Hes_Cpu* this )
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{
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this->cpu_state = &this->cpu_state_;
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}
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// Reset hes cpu
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void Cpu_reset( struct Hes_Cpu* this );
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// Set end_time and run CPU from current time. Returns true if any illegal
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// instructions were encountered.
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bool Cpu_run( struct Hes_Emu* this, hes_time_t end_time );
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// Time of ning of next instruction to be executed
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static inline hes_time_t Cpu_time( struct Hes_Cpu* this )
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{
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return this->cpu_state->time + this->cpu_state->base;
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}
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static inline void Cpu_set_time( struct Hes_Cpu* this, hes_time_t t ) { this->cpu_state->time = t - this->cpu_state->base; }
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static inline void Cpu_adjust_time( struct Hes_Cpu* this, int delta ) { this->cpu_state->time += delta; }
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#define HES_CPU_PAGE( addr ) ((unsigned) (addr) >> page_bits)
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#ifdef BLARGG_NONPORTABLE
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#define HES_CPU_OFFSET( addr ) (addr)
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#else
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#define HES_CPU_OFFSET( addr ) ((addr) & (page_size - 1))
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#endif
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static inline uint8_t const* Cpu_get_code( struct Hes_Cpu* this, hes_addr_t addr )
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{
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return this->cpu_state_.code_map [HES_CPU_PAGE( addr )] + HES_CPU_OFFSET( addr );
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}
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static inline void update_end_time( struct Hes_Cpu* this, hes_time_t end, hes_time_t irq )
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{
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if ( end > irq && !(this->r.flags & irq_inhibit_mask) )
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end = irq;
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this->cpu_state->time += this->cpu_state->base - end;
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this->cpu_state->base = end;
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}
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static inline hes_time_t Cpu_end_time( struct Hes_Cpu* this ) { return this->end_time_; }
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static inline void Cpu_set_irq_time( struct Hes_Cpu* this, hes_time_t t )
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{
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this->irq_time_ = t;
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update_end_time( this, this->end_time_, t );
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}
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static inline void Cpu_set_end_time( struct Hes_Cpu* this, hes_time_t t )
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{
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this->end_time_ = t;
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update_end_time( this, t, this->irq_time_ );
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}
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static inline void Cpu_end_frame( struct Hes_Cpu* this, hes_time_t t )
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{
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assert( this->cpu_state == &this->cpu_state_ );
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this->cpu_state_.base -= t;
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if ( this->irq_time_ < future_time ) this->irq_time_ -= t;
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if ( this->end_time_ < future_time ) this->end_time_ -= t;
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}
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static inline void Cpu_set_mmr( struct Hes_Cpu* this, int reg, int bank, void const* code )
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{
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assert( (unsigned) reg <= page_count ); // allow page past end to be set
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assert( (unsigned) bank < 0x100 );
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this->mmr [reg] = bank;
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byte const* p = STATIC_CAST(byte const*,code) - HES_CPU_OFFSET( reg << page_bits );
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this->cpu_state->code_map [reg] = p;
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this->cpu_state_.code_map [reg] = p;
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}
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#endif
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