user/lib: shared libdraw for framebuffer handling

1 files changed, 43 insertions, 0 deletions

diff --git a/src/user/lib/draw/flush.c b/src/user/lib/draw/flush.c
new file mode 100644
index 0000000..060fdaf
--- /dev/null
+++ b/src/user/lib/draw/flush.c
@@ -0,0 +1,43 @@
+#include <camellia/execbuf.h>
+#include <camellia/syscalls.h>
+#include <user/lib/draw/draw.h>
+
+static void flush_combined(struct rect pix, struct framebuf *fb) {
+	size_t low  = fb->pitch * pix.y1 + 4 * pix.x1;
+	size_t high = fb->pitch * pix.y2 + 4 * pix.y2 + 4;
+	_syscall_write(fb->fd, fb->b + low, high - low, low, 0);
+}
+
+static void flush_split(struct rect pix, struct framebuf *fb) {
+	static uint64_t execbuf[EXECBUF_MAX_LEN / sizeof(uint64_t)];
+	size_t epos = 0;
+	if (7 * (pix.y2 - pix.y1) * sizeof(uint64_t) >= sizeof execbuf) {
+		flush_combined(pix, fb);
+		return;
+	}
+
+	for (uint32_t y = pix.y1; y < pix.y2; y++) {
+		size_t low  = fb->pitch * y + 4 * pix.x1;
+		size_t high = fb->pitch * y + 4 * pix.x2 + 4;
+
+		execbuf[epos++] = EXECBUF_SYSCALL;
+		execbuf[epos++] = _SYSCALL_WRITE;
+		execbuf[epos++] = fb->fd;
+		execbuf[epos++] = (uintptr_t)fb->b + low;
+		execbuf[epos++] = high - low;
+		execbuf[epos++] = low;
+		execbuf[epos++] = 0;
+	}
+	_syscall_execbuf(execbuf, epos * sizeof(uint64_t));
+}
+
+void dirty_flush(struct rect *d, struct framebuf *fb) {
+	if (~d->x1 == 0) return;
+	if (d->x2 >= fb->width)  d->x2 = fb->width - 1;
+	if (d->y2 >= fb->height) d->y2 = fb->height - 1;
+
+	/* the threshold is mostly arbitrary, wasn't based on any real benchmarks */
+	if (d->x2 - d->x1 > fb->width - 600) flush_combined(*d, fb);
+	else flush_split(*d, fb);
+	dirty_reset(d);
+}