Add assembly sandglass_get_tsc function.

3 files changed, 87 insertions, 0 deletions

diff --git a/src/sandglass.h b/src/sandglass.h
index 777a3df..412f5e3 100644
--- a/src/sandglass.h
+++ b/src/sandglass.h
@@ -147,6 +147,13 @@ int sandglass_elapse(sandglass_t *sandglass);
     sandglass_elapse(sandglass);                                               \
   } while (0)
 
+/*
+ * Low-level API
+ */
+
+/* Read the time stamp counter */
+long sandglass_get_tsc();
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/src/x86/tsc-x86.s b/src/x86/tsc-x86.s
new file mode 100644
index 0000000..570b8af
--- /dev/null
+++ b/src/x86/tsc-x86.s
@@ -0,0 +1,40 @@
+/*************************************************************************
+ * Copyright (C) 2008 Tavian Barnes <tavianator@gmail.com>               *
+ *                                                                       *
+ * This file is part of The Sandglass Library.                           *
+ *                                                                       *
+ * The Sandglass Library is free software; you can redistribute it       *
+ * and/or modify it under the terms of the GNU Lesser General Public     *
+ * License as published by the Free Software Foundation; either version  *
+ * 3 of the License, or (at your option) any later version.              *
+ *                                                                       *
+ * The Sandglass Library is distributed in the hope that it will be      *
+ * useful, but WITHOUT ANY WARRANTY; without even the implied warranty   *
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU  *
+ * Lesser General Public License for more details.                       *
+ *                                                                       *
+ * You should have received a copy of the GNU Lesser General Public      *
+ * License along with this program.  If not, see                         *
+ * <http://www.gnu.org/licenses/>.                                       *
+ *************************************************************************/
+
+/*
+ * Return the time stamp counter, and serialize the instruction
+ */
+
+        .text
+/* long sandglass_get_tsc(); */
+.globl sandglass_get_tsc
+        .type sandglass_get_tsc, @function
+sandglass_get_tsc:
+        pushl %ebx              /* Callee-save register, clobbered by cpuid */
+        pushl %esi
+        cpuid                   /* Serialize */
+        rdtsc                   /* Read time stamp counter */
+        movl %eax, %esi         /* Store tsc */
+        cpuid                   /* Serialize again */
+        movl %esi, %eax
+        popl %esi
+        popl %ebx
+        ret
+        .size sandglass_get_tsc, .-sandglass_get_tsc
diff --git a/src/x86_64/tsc-x86_64.s b/src/x86_64/tsc-x86_64.s
new file mode 100644
index 0000000..da33191
--- /dev/null
+++ b/src/x86_64/tsc-x86_64.s
@@ -0,0 +1,40 @@
+/*************************************************************************
+ * Copyright (C) 2008 Tavian Barnes <tavianator@gmail.com>               *
+ *                                                                       *
+ * This file is part of The Sandglass Library.                           *
+ *                                                                       *
+ * The Sandglass Library is free software; you can redistribute it       *
+ * and/or modify it under the terms of the GNU Lesser General Public     *
+ * License as published by the Free Software Foundation; either version  *
+ * 3 of the License, or (at your option) any later version.              *
+ *                                                                       *
+ * The Sandglass Library is distributed in the hope that it will be      *
+ * useful, but WITHOUT ANY WARRANTY; without even the implied warranty   *
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU  *
+ * Lesser General Public License for more details.                       *
+ *                                                                       *
+ * You should have received a copy of the GNU Lesser General Public      *
+ * License along with this program.  If not, see                         *
+ * <http://www.gnu.org/licenses/>.                                       *
+ *************************************************************************/
+
+/*
+ * Return the time stamp counter, and serialize the instruction
+ */
+
+        .text
+/* long sandglass_get_tsc(); */
+.globl sandglass_get_tsc
+        .type sandglass_get_tsc, @function
+ticks:
+        movq %rbx, %rdi         /* Callee-save register, clobbered by cpuid */
+        cpuid                   /* Serialize */
+        rdtsc                   /* Read time stamp counter */
+        shlq $32, %rdx
+        orq %rdx, %rax
+        movq %rax, %rsi
+        cpuid                   /* Serialize again */
+        movq %rsi, %rax
+        movq %rdi, %rbx
+        ret
+        .size sandglass_get_tsc, .-sandglass_get_tsc