70 lines
1.7 KiB
C
70 lines
1.7 KiB
C
#include <gint/display.h>
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#include <gint/kmalloc.h>
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#include <gint/config.h>
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/* Up to two VRAM pointers can be set, for triple buffering. */
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static uint16_t *vram_1 = NULL, *vram_2 = NULL;
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/* Current VRAM pointer, always equal to either vram_1 or vram_2. */
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uint16_t *gint_vram = NULL;
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bool dvram_init(void)
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{
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int const MARGIN = 32;
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/* Leave MARGIN bytes on each side of the region; this enables some
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important optimizations in the image renderer. We also add another
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32 bytes so we can manually 32-align the region */
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uint32_t region = (uint32_t)kmalloc(DWIDTH*DHEIGHT*2 + MARGIN*2 + 32,
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#if !defined(GINT_NO_OS_STACK)
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"_ostk"
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#else
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NULL
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#endif
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);
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if(region == 0)
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return false;
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/* 32-align the region */
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region = (region + 31) & -32;
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/* Skip a MARGIN */
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region += MARGIN;
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/* Use an uncached address */
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region = (region & 0x1fffffff) | 0xa0000000;
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/* Don't enable triple buffering by default */
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vram_1 = (void *)region;
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vram_2 = vram_1;
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gint_vram = vram_1;
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return true;
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}
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/* dsetvram(): Control video RAM address and triple buffering */
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void dsetvram(uint16_t *new_vram_1, uint16_t *new_vram_2)
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{
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if(!new_vram_1 && !new_vram_2) return;
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if(!new_vram_1) new_vram_1 = new_vram_2;
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if(!new_vram_2) new_vram_2 = new_vram_1;
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if(gint_vram == vram_1)
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gint_vram = new_vram_1;
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else if(gint_vram == vram_2)
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gint_vram = new_vram_2;
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vram_1 = new_vram_1;
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vram_2 = new_vram_2;
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}
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/* dgetvram(): Get VRAM addresses */
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void dgetvram(uint16_t **ptr_vram_1, uint16_t **ptr_vram_2)
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{
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if(ptr_vram_1) *ptr_vram_1 = vram_1;
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if(ptr_vram_2) *ptr_vram_2 = vram_2;
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}
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/* dvram_switch(): Triple buffering switch
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This function is not part of the API; it is used only by dupdate(). */
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void dvram_switch(void)
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{
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gint_vram = (gint_vram == vram_1) ? vram_2 : vram_1;
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}
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