1 files changed, 58 insertions, 0 deletions
diff --git a/libsyscalls_get_integer_alignment.c b/libsyscalls_get_integer_alignment.c
new file mode 100644
index 0000000..7802a06
--- /dev/null
+++ b/libsyscalls_get_integer_alignment.c
@@ -0,0 +1,58 @@
+/* See LICENSE file for copyright and license details. */
+#include "common.h"
+
+
+#include "generated/integers.c"
+
+enum libsyscalls_error
+libsyscalls_get_integer_alignment(enum libsyscalls_os os, enum libsyscalls_arch arch, unsigned width_in_bits, unsigned *alignment_out)
+{
+	unsigned maxalign;
+
+	if (!width_in_bits)
+		return LIBSYSCALLS_E_INVAL;
+
+	switch ((int)arch) {
+	case LIBSYSCALLS_ARCH_M68K: /* https://m680x0.github.io/doc/abi.html#scalar-types
+	                             * https://lists.nongnu.org/archive/html/qemu-devel/2015-02/msg04797.html */
+		maxalign = 16;
+		break;
+
+	case LIBSYSCALLS_ARCH_I386:
+		maxalign = 32;
+		break;
+
+	case LIBSYSCALLS_ARCH_AMD64:
+	case LIBSYSCALLS_ARCH_AMD64_X32:
+	case LIBSYSCALLS_ARCH_ALPHA: /* https://static.lwn.net/images/pdf/LDD3/ch11.pdf */
+	case LIBSYSCALLS_ARCH_IA64: /* https://static.lwn.net/images/pdf/LDD3/ch11.pdf */
+	case LIBSYSCALLS_ARCH_MIPS_O32: /* https://static.lwn.net/images/pdf/LDD3/ch11.pdf */
+	case LIBSYSCALLS_ARCH_PARISC_32: /* https://www.ece.lsu.edu/ee4720/doc/pa1.1.pdf (page 26) */
+	case LIBSYSCALLS_ARCH_PARISC_64:
+	case LIBSYSCALLS_ARCH_POWERPC_32: /* https://static.lwn.net/images/pdf/LDD3/ch11.pdf */
+	case LIBSYSCALLS_ARCH_SPARC_32: /* https://www.gaisler.com/doc/sparcv8.pdf (page 46) */
+	case LIBSYSCALLS_ARCH_SPARC_64: /* https://static.lwn.net/images/pdf/LDD3/ch11.pdf */
+	case LIBSYSCALLS_ARCH_XTENSA: /* https://loboris.eu/ESP32/Xtensa_lx%20Overview%20handbook.pdf (page 97) */
+		maxalign = 64;
+		break;
+
+	default:
+		return LIBSYSCALLS_E_ARCHNOSUP;
+	}
+
+	if (width_in_bits & (width_in_bits - 1) || width_in_bits & 7 || width_in_bits > 64)
+		return LIBSYSCALLS_E_NOSUCHTYPE;
+	*alignment_out = width_in_bits < maxalign ? width_in_bits : maxalign;
+
+#define CASE(UPPERCASE, LOWERCASE)\
+	case LIBSYSCALLS_OS_##UPPERCASE:\
+		return get_##LOWERCASE##_integer_alignment(arch, width_in_bits, alignment_out)
+
+	switch ((int)os) {
+	LIST_OSES(CASE, ;);
+	default:
+		return LIBSYSCALLS_E_OSNOSUP;
+	}
+
+#undef CASE
+}