Changeset 508b0df1 in mainline for uspace/lib/c/arch/arm32/src/atomic.c

Timestamp:

2018-09-06T20:21:52Z (6 years ago)

Author:

Jiří Zárevúcky <jiri.zarevucky@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

78de83de, fc10e1b

Parents:

4621d23

git-author:

Jiří Zárevúcky <jiri.zarevucky@…> (2018-08-13 03:53:39)

git-committer:

Jiří Zárevúcky <jiri.zarevucky@…> (2018-09-06 20:21:52)

Message:

Remove uspace <atomic.h>, use <stdatomic.h> instead

File:

• uspace/lib/c/arch/arm32/src/atomic.c (modified) (1 diff)

uspace/lib/c/arch/arm32/src/atomic.c

@@ -81 +81 @@
 }
 
+unsigned short __atomic_fetch_add_2(volatile unsigned short *mem, unsigned short val, int model)
+{
+        (void) model;
+
+        unsigned short ret;
+
+        /*
+         * The following instructions between labels 1 and 2 constitute a
+         * Restartable Atomic Seqeunce. Should the sequence be non-atomic,
+         * the kernel will restart it.
+         */
+        asm volatile (
+            "1:\n"
+            "   adr %[ret], 1b\n"
+            "   str %[ret], %[rp0]\n"
+            "   adr %[ret], 2f\n"
+            "   str %[ret], %[rp1]\n"
+            "   ldrh %[ret], %[addr]\n"
+            "   add %[ret], %[ret], %[imm]\n"
+            "   strh %[ret], %[addr]\n"
+            "2:\n"
+            : [ret] "=&r" (ret),
+              [rp0] "=m" (ras_page[0]),
+              [rp1] "=m" (ras_page[1]),
+              [addr] "+m" (*mem)
+            : [imm] "r" (val)
+        );
+
+        ras_page[0] = 0;
+        ras_page[1] = 0xffffffff;
+
+        return ret - val;
+}
+
 unsigned __atomic_fetch_add_4(volatile unsigned *mem, unsigned val, int model)
 {