historical/m0-applesillicon.git/xnu-qemu-arm64-5.1.0/roms/openbios/arch/ppc/timebase.S
2024-01-16 11:20:27 -06:00

33 lines
936 B
ArmAsm

#include "asm/asmdefs.h"
#include "asm/processor.h"
/*
* unsigned long long _get_ticks(void);
*/
_GLOBAL(_get_ticks):
1: mftbu r3
mftb r4
mftbu r5
cmpw 0,r3,r5
bne 1b
blr
/*
* Delay for a number of ticks
*/
_GLOBAL(_wait_ticks):
mflr r8 /* save link register */
mr r7, r3 /* save tick count */
bl BRANCH_LABEL(_get_ticks) /* Get start time */
/* Calculate end time */
addc r7, r4, r7 /* Compute end time lower */
addze r6, r3 /* and end time upper */
1: bl BRANCH_LABEL(_get_ticks) /* Get current time */
subfc r4, r4, r7 /* Subtract current time from end time */
subfe. r3, r3, r6
bge 1b /* Loop until time expired */
mtlr r8 /* restore link register */
blr