ref: 81c844499bad5a0ca67be38fd6a90d254f208dd8
parent: 90c65adbd50f21bc2802438d03451c7845b8e43f
author: Ori Bernstein <ori@eigenstate.org>
date: Mon May 13 23:01:33 EDT 2024
atomic: add power64 implementation (untested) let's crib what go has, and use it for the upcoming power64 9front port.
--- /dev/null
+++ b/atomic-power64.s
@@ -1,0 +1,106 @@
+/* get variants */
+TEXT agetl+0(SB),1,$0
+ SYNC
+ // See ISA 3.0B section B.2.3, "Safe Fetch"
+ MOVWZ 0(R3), R3
+ CMPW R3, R3, CR7
+ BC 4, 30, 1(PC) // bne- cr7,0x4
+ ISYNC
+ MOVW R3, ret+8(FP)
+ RETURN
+
+TEXT agetv+0(SB),1,$0
+TEXT agetp+0(SB),1,$0
+ SYNC
+ // See ISA 3.0B section B.2.3, "Safe Fetch"
+ MOVD 0(R3), R3
+ CMP R3, R3, CR7
+ BC 4, 30, 1(PC) // bne- cr7,0x4
+ ISYNC
+ MOVD R3, ret+8(FP)
+ RETURN
+
+/* set variants */
+TEXT asetl+0(SB),1,$0
+ MOVW val+8(FP), R4
+ SYNC
+ MOVW R4, 0(R3)
+ RETURN
+
+TEXT asetv+0(SB),1,$0
+TEXT asetp+0(SB),1,$0
+ MOVD val+8(FP), R4
+ SYNC
+ MOVD R4, 0(R3)
+ RETURN
+
+/* inc variants */
+TEXT aincl+0(SB),1,$0
+ MOVD R3, R4
+ MOVW delta+8(FP), R5
+ LWSYNC
+ LWAR (R4), R3
+ ADD R5, R3
+ STWCCC R3, (R4)
+ BNE -3(PC)
+ MOVW R3, ret+16(FP)
+ RETURN
+
+TEXT aincv+0(SB),1,$0
+TEXT aincp+0(SB),1,$0
+ MOVD delta+8(FP), R5
+ LWSYNC
+ LDAR (R3), R4
+ ADD R5, R4
+ STDCCC R4, (R3)
+ BNE -3(PC)
+ MOVD R4, ret+16(FP)
+ RETURN
+
+/* cas variants */
+TEXT acasl+0(SB),1,$0
+ MOVWZ old+8(FP), R4
+ MOVWZ new+12(FP), R5
+ LWSYNC
+casagain:
+ LWAR (R3), R6
+ CMPW R6, R4
+ BNE casfail
+ STWCCC R5, (R3)
+ BNE casagain
+ MOVD $1, R3
+ LWSYNC
+ MOVB R3, ret+16(FP)
+ RETURN
+casfail:
+ LWSYNC
+ MOVB R0, ret+16(FP)
+ RETURN
+
+TEXT acasv+0(SB),1,$0
+TEXT acasp+0(SB),1,$0
+ MOVD old+8(FP), R4
+ MOVD new+16(FP), R5
+ LWSYNC
+cas64again:
+ LDAR (R3), R6
+ CMP R6, R4
+ BNE cas64fail
+ STDCCC R5, (R3)
+ BNE cas64again
+ MOVD $1, R3
+ LWSYNC
+ MOVB R3, ret+24(FP)
+ RETURN
+cas64fail:
+ LWSYNC
+ MOVB R0, ret+24(FP)
+ RETURN
+
+/* barriers */
+TEXT coherence+0(SB),1,$0
+ // LWSYNC is the "export" barrier recommended by Power ISA
+ // v2.07 book II, appendix B.2.2.2.
+ // LWSYNC is a load/load, load/store, and store/store barrier.
+ LWSYNC
+ RETURN