ref: 76f41120c1d9685ea78e940bcaf23db79e17f4cd
parent: 65bcb3493e643608ca4fbc77baf2ebef9a1244e6
author: rodri <rgl@antares-labs.eu>
date: Thu Nov 9 12:07:05 EST 2023
track nanosec.c and fix some things.
--- a/main.c
+++ b/main.c
@@ -207,14 +207,14 @@
}
void
-shade(Memimage *dst, Memimage *(*shader)(Point))
+shade(Memimage *dst, Rectangle r, Memimage *(*shader)(Point))
{Point p;
Memimage *c;
- p = ZP;
- for(; p.y < Dy(dst->r); p.y++)
- for(p.x = 0; p.x < Dx(dst->r); p.x++)
+ p = r.min;
+ for(; p.y < r.max.y; p.y++)
+ for(p.x = 0; p.x < r.max.x; p.x++)
if((c = shader(p)) != nil)
pixel(dst, p, c);
}
@@ -231,10 +231,8 @@
t.p2 = Pt2(240,40,1);
bbox = Rect(
- min(min(t.p0.x, t.p1.x), t.p2.x),
- min(min(t.p0.y, t.p1.y), t.p2.y),
- max(max(t.p0.x, t.p1.x), t.p2.x),
- max(max(t.p0.y, t.p1.y), t.p2.y)
+ min(min(t.p0.x, t.p1.x), t.p2.x), min(min(t.p0.y, t.p1.y), t.p2.y),
+ max(max(t.p0.x, t.p1.x), t.p2.x), max(max(t.p0.y, t.p1.y), t.p2.y)
);
if(!ptinrect(p, bbox))
return nil;
@@ -250,7 +248,7 @@
{lockdisplay(display);
draw(screen, screen->r, display->black, nil, ZP);
- loadimage(screen, screen->r, byteaddr(fb, fb->r.min), bytesperline(fb->r, fb->depth)*Dy(fb->r));
+ loadimage(screen, fb->r, byteaddr(fb, fb->r.min), bytesperline(fb->r, fb->depth)*Dy(fb->r));
flushimage(display, 1);
unlockdisplay(display);
}
@@ -334,7 +332,7 @@
triangle(fb, Pt(400,230), Pt(450,180), Pt(150, 320), red);
t0 = nanosec();
- shade(fb, triangleshader);
+ shade(fb, rectsubpt(fb->r, fb->r.min), triangleshader);
t1 = nanosec();
fprint(2, "shader took %lludns\n", t1-t0);
--- /dev/null
+++ b/nanosec.c
@@ -1,0 +1,109 @@
+#include <u.h>
+#include <libc.h>
+#include <tos.h>
+
+/*
+ * This code is a mixture of cpuid(1) and the nanosec() found in vmx,
+ * in order to force the use of nsec(2) in case we are running in a
+ * virtualized environment where the clock is mis-bhyve-ing.
+ */
+
+typedef struct Res {+ ulong ax, bx, cx, dx;
+} Res;
+
+static uchar _cpuid[] = {+ 0x5E, /* POP SI (PC) */
+ 0x5D, /* POP BP (Res&) */
+ 0x58, /* POP AX */
+ 0x59, /* POP CX */
+
+ 0x51, /* PUSH CX */
+ 0x50, /* PUSH AX */
+ 0x55, /* PUSH BP */
+ 0x56, /* PUSH SI */
+
+ 0x31, 0xDB, /* XOR BX, BX */
+ 0x31, 0xD2, /* XOR DX, DX */
+
+ 0x0F, 0xA2, /* CPUID */
+
+ 0x89, 0x45, 0x00, /* MOV AX, 0(BP) */
+ 0x89, 0x5d, 0x04, /* MOV BX, 4(BP) */
+ 0x89, 0x4d, 0x08, /* MOV CX, 8(BP) */
+ 0x89, 0x55, 0x0C, /* MOV DX, 12(BP) */
+ 0xC3, /* RET */
+};
+
+static Res (*cpuid)(ulong ax, ulong cx) = (Res(*)(ulong, ulong)) _cpuid;
+
+/*
+ * nsec() is wallclock and can be adjusted by timesync
+ * so need to use cycles() instead, but fall back to
+ * nsec() in case we can't
+ */
+uvlong
+nanosec(void)
+{+ static uvlong fasthz, xstart;
+ char buf[13], path[128];
+ ulong w;
+ uvlong x, div;
+ int fd;
+ Res r;
+
+ if(fasthz == ~0ULL)
+ return nsec() - xstart;
+
+ if(fasthz == 0){+ /* first long in a.out header */
+ snprint(path, sizeof path, "/proc/%d/text", getpid());
+ fd = open(path, OREAD);
+ if(fd < 0)
+ goto Wallclock;
+ if(read(fd, buf, 4) != 4){+ close(fd);
+ goto Wallclock;
+ }
+ close(fd);
+
+ w = ((ulong *) buf)[0];
+
+ switch(w){+ default:
+ goto Wallclock;
+ case 0x978a0000: /* amd64 */
+ /* patch out POP BP -> POP AX */
+ _cpuid[1] = 0x58;
+ case 0xeb010000: /* 386 */
+ break;
+ }
+ segflush(_cpuid, sizeof(_cpuid));
+
+ r = cpuid(0x40000000, 0);
+ ((ulong *) buf)[0] = r.bx;
+ ((ulong *) buf)[1] = r.cx;
+ ((ulong *) buf)[2] = r.dx;
+ buf[12] = 0;
+
+ if(strstr(buf, "bhyve") != nil)
+ goto Wallclock;
+
+ if(_tos->cyclefreq){+ fasthz = _tos->cyclefreq;
+ cycles(&xstart);
+ } else {+Wallclock:
+ fasthz = ~0ULL;
+ xstart = nsec();
+ }
+ return 0;
+ }
+ cycles(&x);
+ x -= xstart;
+
+ /* this is ugly */
+ for(div = 1000000000ULL; x < 0x1999999999999999ULL && div > 1 ; div /= 10ULL, x *= 10ULL);
+
+ return x / (fasthz / div);
+}