added atomic_dec32le0 for sem/mutex lock

2022-08-31 10:10:35 +02:00
parent 5424edfe5e
commit d071c0957b
5 changed files with 22 additions and 7 deletions
--- a/atomic.S
+++ b/atomic.S
@@ -20,10 +20,24 @@ atomic_inc32:
 .type   atomic_dec32, %function

 atomic_dec32:
-2:      ldrex           r2, [r0]
+1:      ldrex           r2, [r0]
        sub             r2, r2, r1
        strex           r3, r2, [r0]
        teq             r3, #0
-        bne             2b
+        bne             1b
+        mov             r0, r2
+        bx              lr
+
+.globl  atomic_dec32le0
+.type   atomic_dec32le0, %function
+
+atomic_dec32le0:
+1:      ldrex           r2, [r0]
+        cmp             r2, #0
+        ble             1b
+        sub             r2, r2, r1
+        strex           r3, r2, [r0]
+        teq             r3, #0
+        bne             1b
        mov             r0, r2
        bx              lr