1 // intlevel-setmin.S - Interrupt related assembler code - _xtos_set_min_intlevel
3 // Copyright (c) 2004-2010 Tensilica Inc.
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24 #include <xtensa/coreasm.h>
25 #include <xtensa/config/specreg.h>
26 #include "xtos-internal.h"
29 /***************************************************************************
30 * unsigned _xtos_set_min_intlevel(int intlevel);
32 * _xtos_set_min_intlevel() is identical to _xtos_set_intlevel() except
33 * that it will not lower the current interrupt level. Instead,
34 * it ensures that the current interrupt level is at least as high
37 * NOTE: This version allows the 'intlevel' parameter to be computed
38 * at run-time, and thus is longer. It is much more efficient, and
39 * highly recommented, to use the XTOS_SET_MIN_INTLEVEL(intlevel) macro instead
40 * (which requires a constant intlevel).
45 .global _xtos_set_min_intlevel
46 .type _xtos_set_min_intlevel,@function
47 _xtos_set_min_intlevel:
49 #if XCHAL_HAVE_INTERRUPTS
51 /* In XEA2, we can simply safely set PS.INTLEVEL directly: */
52 rsr a3, PS // get old (current) PS.INTLEVEL
54 extui a2, a2, 0, 4 // keep only INTLEVEL bits of parameter
55 extui a5, a3, 0, 4 // look at old PS.INTLEVEL
56 sub a5, a2, a5 // new.intlevel - old.intlevel
57 and a4, a4, a3 // mask out PS.INTLEVEL
58 or a4, a4, a2 // insert requested INTLEVEL
59 movltz a4, a3, a5 // keep same PS if already higher than requested
60 wsr a4, PS // update PS.INTLEVEL
61 extui a2, a3, 0, 4 // return only old PS.INTLEVEL field
62 rsync // wait for WSR to PS to complete
64 /* In XEA1, we have to rely on INTENABLE register virtualization: */
65 movi a4, Xthal_intlevel_andbelow_mask
66 extui a3, a2, 0, 4 // keep only INTLEVEL bits of parameter
67 addx4 a5, a3, a4 // index mask to use
68 l32i a3, a5, 0 // get mask of interrupts at requested intlevel and below
69 movi a5, -1 // all 1's
70 movi a4, _xtos_intstruct
71 xor a3, a3, a5 // mask of interrupts at intlevels above the requested one (to enable)
72 xtos_lock a7 // MUST USE highest address register of function to avoid window overflows in critical section
73 l32i a2, a4, XTOS_VPRI_ENABLED_OFS // return old xtos_vpri_enabled (current vpri)
74 l32i a5, a4, XTOS_ENABLED_OFS // a5 = xtos_enabled
75 and a3, a3, a2 // make sure we don't enable any new interrupts
76 s32i a3, a4, XTOS_VPRI_ENABLED_OFS // set new xtos_vpri_enabled (current vpri)
77 and a5, a5, a3 // a5 = xtos_enabled & xtos_vpri_enabled
81 #endif /*XCHAL_HAVE_INTERRUPTS*/
84 .size _xtos_set_min_intlevel, . - _xtos_set_min_intlevel