158 lines
2.3 KiB
C
158 lines
2.3 KiB
C
//---
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//
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// gint core/drawing module: gray
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//
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// Runs the gray engine and handles drawing for the dual-buffer system.
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//
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//---
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#include <gray.h>
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#include <screen.h>
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#include <timer.h>
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#include <mpu.h>
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static int internal_vrams[3][256];
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static const void *vrams[4];
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static int current = 0;
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static int delays[2];
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static int runs = 0;
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#define GRAY_PRESCALER TIMER_Po_64
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//---
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// Engine control.
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//---
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/*
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gray_start()
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Starts the gray engine. The control of the screen is transferred to the
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gray engine.
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*/
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void gray_start(void)
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{
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if(runs) return;
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timer_start(TIMER_GRAY, delays[0], GRAY_PRESCALER, gray_interrupt, 0);
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current &= 1;
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runs = 1;
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}
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/*
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gray_stop()
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Stops the gray engine. The monochrome display system takes control of
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the video ram.
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*/
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void gray_stop(void)
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{
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if(!runs) return;
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timer_stop(TIMER_GRAY);
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runs = 0;
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display_useVRAM(display_getLocalVRAM());
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}
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/*
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gray_setDelays()
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Changes the gray engine delays.
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*/
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void gray_setDelays(int light, int dark)
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{
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delays[0] = light;
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delays[1] = dark;
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}
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//---
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// Engine information.
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//---
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/*
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gray_runs()
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Returns 1 if the gray engine is running, 0 otherwise.
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*/
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inline int gray_runs(void)
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{
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return runs;
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}
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/*
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gray_lightVRAM()
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Returns the module's gray vram address.
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*/
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void *gray_lightVRAM(void)
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{
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return (void *)vrams[~current & 2];
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}
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/*
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gray_lightVRAM()
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Returns the module's dark vram address.
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*/
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void *gray_darkVRAM(void)
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{
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return (void *)vrams[(~current & 2) | 1];
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}
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/*
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gray_getDelays()
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Returns the gray engine delays. Pointers are not set if NULL.
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*/
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void gray_getDelays(int *light, int *dark)
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{
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if(light) *light = delays[0];
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if(dark) *dark = delays[1];
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}
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//---
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// Drawing.
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//---
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/*
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gupdate()
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Swaps the vram buffer sets.
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*/
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inline void gupdate(void)
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{
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current ^= 2;
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}
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//---
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// Interrupt control and initialization.
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//---
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/*
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gray_interrupt()
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Answers a timer interrupt. Swaps the buffers.
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*/
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void gray_interrupt(void)
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{
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timer_reload(TIMER_GRAY, delays[(~current) & 1]);
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screen_display(vrams[current]);
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current ^= 1;
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}
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/*
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gray_init()
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Initializes the gray engine.
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*/
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void gray_init(void)
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{
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vrams[0] = (const void *)display_getLocalVRAM();
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vrams[1] = (const void *)internal_vrams[0];
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vrams[2] = (const void *)internal_vrams[1];
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vrams[3] = (const void *)internal_vrams[2];
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delays[0] = isSH3() ? 985 : 994;
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delays[1] = 1609;
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}
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