From: Keith Packard <keithp@keithp.com>
Date: Tue, 19 Mar 2019 00:15:16 +0000 (-0700)
Subject: altos: ARM ABI requires 8-byte aligned stack
X-Git-Tag: 1.9.1~1^2~106
X-Git-Url: https://git.gag.com/?p=fw%2Faltos;a=commitdiff_plain;h=a2df970fca0e719e4b32e1642803590ff7bbd1ee;ds=sidebyside

altos: ARM ABI requires 8-byte aligned stack

This makes doubles on the stack (as for var-args functions) work

Signed-off-by: Keith Packard <keithp@keithp.com>
---

diff --git a/src/kernel/ao_task.h b/src/kernel/ao_task.h
index d27ef060..03b62969 100644
--- a/src/kernel/ao_task.h
+++ b/src/kernel/ao_task.h
@@ -26,10 +26,10 @@
 #define HAS_TASK_INFO 1
 #endif
 
-/* arm stacks must be 32-bit aligned */
+/* arm stacks must be 64-bit aligned */
 #ifndef AO_STACK_ALIGNMENT
 #ifdef __arm__
-#define AO_STACK_ALIGNMENT __attribute__ ((aligned(4)))
+#define AO_STACK_ALIGNMENT __attribute__ ((aligned(8)))
 #else
 #define AO_STACK_ALIGNMENT
 #endif
@@ -50,11 +50,11 @@ struct ao_task {
 	struct ao_list	queue;
 	struct ao_list	alarm_queue;
 #endif
-	/* Provide both 32-bit and 8-bit stacks, always 32-bit aligned */
+	/* Provide both 32-bit and 8-bit stacks */
 	union {
 		uint32_t stack32[AO_STACK_SIZE>>2];
 		uint8_t stack8[AO_STACK_SIZE];
-	};
+	} AO_STACK_ALIGNMENT;
 #if HAS_SAMPLE_PROFILE
 	uint32_t ticks;
 	uint32_t yields;