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// TITLE("Byte and Short Emulation")//++////// Copyright (c) 1995 Digital Equipment Corporation//// Module Name://// byteme.s//// Abstract://// This module implements the code to perform atomic store operations// on bytes and shorts (words).//// Atomic byte and short opcodes have been added into the Alpha// architecture as of Alpha 21164A or EV56. In chips 21164 and prior,// an illegal instruction will occur and an exception will lead them here.//// Author://// Wim Colgate, May 18th, 1995// Tom Van Baak, May 18th, 1995//// Environment://// Kernel mode only.//// Revision History:////--
#include "ksalpha.h"
//++//// VOID// KiInterlockedStoreByte(// IN PUCHAR Address,// IN UCHAR Data// )//// Routine Description://// This routine stores the data byte specified by Data to the location// specified by Address. The architecture requires byte granularity,// so locking is necessary.//// Arguments://// Address(a0) - Supplies a pointer to byte data value.// Data(a1) - Supplied the byte data value to store.//// Return Value://// None////--
LEAF_ENTRY(KiInterlockedStoreByte)
bic a0, 3, t0 // clear low 2 bits and a0, 3, t1 // mask of three low bits10: ldl_l t2, 0(t0) // load locked full longword insbl a1, t1, t3 // insert byte low mskbl t2, t1, t2 // mask byte low bis t2, t3, t2 // merge data stl_c t2, 0(t0) // store conditional beq t2, 20f // failed to store, retry, forward ret zero, (ra), 1 // return
20: br zero, 10b // try again
.end KiInterlockedStoreByte //++//// VOID// KiInterlockedStoreWord(// IN PUSHORT Address,// IN USHORT Data// )//// Routine Description://// This routine stores the short data specified by Data to the aligned// location specified by Address. The architecture requires word granularity,// so locking is necessary.//// Arguments://// Address(a0) - Supplies a pointer to an aligned short data value.// Data(a1) - Supplied the short data value to store.//// Return Value://// None////--
LEAF_ENTRY(KiInterlockedStoreWord)
bic a0, 2, t0 // clear low short address bit and a0, 2, t1 // mask of low short address bit10: ldl_l t2, 0(t0) // load locked full longword inswl a1, t1, t3 // insert word low mskwl t2, t1, t2 // mask word low bis t2, t3, t2 // merge data stl_c t2, 0(t0) // store conditional beq t2, 20f // failed to store, retry, forward ret zero, (ra), 1 // return
20: br zero, 10b // try again
.end KiInterlockedStoreWord
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