/* * (C) Copyright 2003, Psyent Corporation <www.psyent.com> * Scott McNutt <smcnutt@psyent.com> * * See file CREDITS for list of people who contributed to this * project. * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License as * published by the Free Software Foundation; either version 2 of * the License, or (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, * MA 02111-1307 USA */ #include <config.h> /************************************************************************* * Register window underflow * * The register window underflow exception occurs whenever the lowest * valid register window is in use (CWP=LO_LIMIT) and a save instruction * is issued. The save moves CWP below LO_LIMIT, %sp is set as normal, * then the exception is generated prior to executing the instruction * after the save. ************************************************************************/ .text .global _cwp_lolimit .align 4 _cwp_lolimit: /* Sixteen words are always allocated by the compiler in every * procedure's stack frame, always starting at %sp, for saving * 'in' and 'local' registers on a window overflow. * * Save the 'global' and 'in' regs on stack. They are restored * at cwp = HI_LIMIT. The 'local' regs aren't in-use at this point. */ sts [%sp,0], %g0 /* Save 'global' regs*/ sts [%sp,1], %g1 sts [%sp,2], %g2 sts [%sp,3], %g3 sts [%sp,4], %g4 sts [%sp,5], %g5 sts [%sp,6], %g6 sts [%sp,7], %g7 sts [%sp,8], %i0 /* Save 'in' regs */ sts [%sp,9], %i1 sts [%sp,10], %i2 sts [%sp,11], %i3 sts [%sp,12], %i4 sts [%sp,13], %i5 sts [%sp,14], %i6 sts [%sp,15], %i7 /* Save current %sp and return address in a global so they are * available at cwp = HI_LIMIT ... where the 'global'/'in' regs * are restored. NOTE: %sp changes with cwp. */ mov %g7, %o7 mov %g6, %sp /* Get LO_LIMIT/HI_LIMIT to know where to start & stop. Note: in * the underflow exception, cwp is __NOT__ guaranteed to be zero. * If the OCI debug module is enabled the reset value for LO_LIMIT * is 2, not 1 -- so cwp can be 1 or 0. */ pfx 2 /* WVALID */ rdctl %g1 mov %g2, %g1 pfx 0 and %g1, 0x1f /* g1 <- LO_LIMIT */ lsri %g2, 5 pfx 0 and %g2,0x1f /* g2 <- HI_LIMIT */ /* Set istatus so cwp = HI_LIMIT after tret */ movi %g5, 0x1f lsli %g5, 4 not %g5 /* mask to clr cwp */ pfx 1 /* istatus */ rdctl %g0 and %g0, %g5 /* clear cwp field */ mov %g4, %g2 lsli %g4, 4 or %g0, %g4 /* cwp = HI_LIMIT */ pfx 1 wrctl %g0 /* update istatus */ /* Now move up the register file, saving as we go. When loop * is first entered, %g1 is at LO_LIMIT. */ 0: restore /* cwp++ */ sts [%sp,0], %l0 /* Save "local" regs*/ sts [%sp,1], %l1 sts [%sp,2], %l2 sts [%sp,3], %l3 sts [%sp,4], %l4 sts [%sp,5], %l5 sts [%sp,6], %l6 sts [%sp,7], %l7 sts [%sp,8], %i0 /* Save 'in' regs */ sts [%sp,9], %i1 sts [%sp,10], %i2 sts [%sp,11], %i3 sts [%sp,12], %i4 sts [%sp,13], %i5 sts [%sp,14], %i6 sts [%sp,15], %i7 cmp %g1, %g2 /* cwp == HI_LIMIT ? */ skps cc_ne /* if so, we're done */ br 1f nop /* delay slot */ inc %g1 /* g1 <- cwp++ */ br 0b nop /* delay slot */ /* At this point cwp = HI_LIMIT, so the global/in regs that were * in place when the underflow occurred must be restored using * the original stack pointer (saved in g6). */ 1: mov %o7, %g7 /* restore return addr */ mov %sp, %g6 /* Restore original sp */ lds %g0, [%sp,0] /* Restore 'global' regs*/ lds %g1, [%sp,1] lds %g2, [%sp,2] lds %g3, [%sp,3] lds %g4, [%sp,4] lds %g5, [%sp,5] lds %g6, [%sp,6] lds %g7, [%sp,7] lds %i0, [%sp,8] /* Restore 'in' regs*/ lds %i1, [%sp,9] lds %i2, [%sp,10] lds %i3, [%sp,11] lds %i4, [%sp,12] lds %i5, [%sp,13] lds %i6, [%sp,14] lds %i7, [%sp,15] tret %o7 /* All done */ /************************************************************************* * Register window overflow * * The register window overflow exception occurs whenever the highest * valid register window is in use (cwp = HI_LIMIT) and a restore * instruction is issued. Control is transferred to the overflow handler * before the instruction following restore is executed. * * When a register window overflow exception is taken, the exception * handler sees cwp at HI_LIMIT. ************************************************************************/ .text .global _cwp_hilimit .align 4 _cwp_hilimit: /* Save 'global'/'in' regs on the stack -- will restore when cwp * is at LO_LIMIT. Locals don't need saving as they are going away. */ sts [%sp,0], %g0 /* Save "global" regs*/ sts [%sp,1], %g1 sts [%sp,2], %g2 sts [%sp,3], %g3 sts [%sp,4], %g4 sts [%sp,5], %g5 sts [%sp,6], %g6 sts [%sp,7], %g7 sts [%sp,8], %i0 /* Save 'in' regs */ sts [%sp,9], %i1 sts [%sp,10], %i2 sts [%sp,11], %i3 sts [%sp,12], %i4 sts [%sp,13], %i5 sts [%sp,14], %i6 sts [%sp,15], %i7 /* The current %sp must be available in global to restore regs * saved on stack. Need return addr as well ;-) */ mov %g7, %o7 mov %g6, %sp /* Get HI_LIMIT & LO_LIMIT */ pfx 2 /* WVALID */ rdctl %g1 mov %g2, %g1 pfx 0 and %g1, 0x1f /* g1 <- LO_LIMIT */ lsri %g2, 5 pfx 0 and %g2,0x1f /* g2 <- HI_LIMIT */ /* Set istatus so cwp = LO_LIMIT after tret */ movi %g5, 0x1f lsli %g5, 4 not %g5 /* mask to clr cwp */ pfx 1 /* istatus */ rdctl %g0 and %g0, %g5 /* clear cwp field */ mov %g4, %g1 /* g4 <- LO_LIMIT */ lsli %g4, 4 or %g0, %g4 /* cwp = LO_LIMIT */ pfx 1 wrctl %g0 /* update istatus */ /* Move to cwp = LO_LIMIT-1 and restore 'in' regs. */ subi %g4,(1 << 4) /* g4 <- LO_LIMIT - 1 */ rdctl %g0 and %g0, %g5 /* clear cwp field */ or %g0, %g4 /* cwp = LO_LIMIT - 1 */ wrctl %g0 /* update status */ nop mov %sp, %g6 /* Restore sp */ lds %i0, [%sp,8] /* Restore 'in' regs */ lds %i1, [%sp,9] lds %i2, [%sp,10] lds %i3, [%sp,11] lds %i4, [%sp,12] lds %i5, [%sp,13] lds %i6, [%sp,14] /* sp in next window */ lds %i7, [%sp,15] /* Starting at LO_LIMIT-1, move up the register file, restoring * along the way. */ 0: restore /* cwp++ */ lds %l0, [%sp,0] /* Restore 'local' regs*/ lds %l1, [%sp,1] lds %l2, [%sp,2] lds %l3, [%sp,3] lds %l4, [%sp,4] lds %l5, [%sp,5] lds %l6, [%sp,6] lds %l7, [%sp,7] lds %i0, [%sp,8] /* Restore 'in' regs */ lds %i1, [%sp,9] lds %i2, [%sp,10] lds %i3, [%sp,11] lds %i4, [%sp,12] lds %i5, [%sp,13] lds %i6, [%sp,14] /* sp in next window */ lds %i7, [%sp,15] cmp %g1, %g2 /* cwp == HI_LIMIT ? */ skps cc_ne /* if so, we're done */ br 1f nop /* delay slot */ inc %g1 /* cwp++ */ br 0b nop /* delay slot */ /* All windows have been updated at this point, but the globals * still need to be restored. Go to cwp = LO_LIMIT-1 to get * some registers to use. */ 1: rdctl %g0 and %g0, %g5 /* clear cwp field */ or %g0, %g4 /* cwp = LO_LIMIT - 1 */ wrctl %g0 /* update status */ nop /* Now there are some registers available to use in restoring * the globals. */ mov %sp, %g6 mov %o7, %g7 lds %g0, [%sp,0] /* Restore "global" regs*/ lds %g1, [%sp,1] lds %g2, [%sp,2] lds %g3, [%sp,3] lds %g4, [%sp,4] lds %g5, [%sp,5] lds %g6, [%sp,6] lds %g7, [%sp,7] /* The tret moves istatus -> status. istatus was already set for * cwp = LO_LIMIT. */ tret %o7 /* done */ /************************************************************************* * Default exception handler * * The default handler passes control to external_interrupt(). So trap * or hardware interrupt hanlders can be installed using the familiar * irq_install_handler(). * * Here, the stack is fixed-up and cwp is incremented prior to calling * external_interrupt(). This lets the underflow and overflow handlers * operate normally during the exception. ************************************************************************/ .text .global _def_xhandler .align 4 _def_xhandler: /* Allocate some stack space: 16 words at %sp to accomodate * a reg window underflow, 8 words to save interrupted task's * 'out' regs (which are now the 'in' regs), 8 words to preserve * the 'global' regs and 3 words to save the return address, * status and istatus. istatus must be saved in the event an * underflow occurs in a dispatched handler. status is saved so * a handler can access it on stack. */ pfx %hi((16+16+3) * 4) subi %fp, %lo((16+16+3) * 4) mov %sp, %fp /* Save the 'global' regs and the interrupted task's 'out' regs * (our 'in' regs) along with the return addr, status & istatus. * First 16 words are for underflow exception. */ rdctl %l0 /* status */ pfx 1 /* istatus */ rdctl %l1 sts [%sp,16+0], %g0 /* Save 'global' regs*/ sts [%sp,16+1], %g1 sts [%sp,16+2], %g2 sts [%sp,16+3], %g3 sts [%sp,16+4], %g4 sts [%sp,16+5], %g5 sts [%sp,16+6], %g6 sts [%sp,16+7], %g7 sts [%sp,16+8], %i0 /* Save 'in' regs */ sts [%sp,16+9], %i1 sts [%sp,16+10], %i2 sts [%sp,16+11], %i3 sts [%sp,16+12], %i4 sts [%sp,16+13], %i5 sts [%sp,16+14], %i6 sts [%sp,16+15], %i7 sts [%sp,16+16], %l0 /* status */ sts [%sp,16+17], %l1 /* istatus */ sts [%sp,16+18], %o7 /* return addr */ /* Move to cwp+1 ... this guarantees cwp is at or above LO_LIMIT. * Need to set IPRI=3 and IE=1 to enable underflow exceptions. * NOTE: only the 'out' regs have been saved ... can't touch * the 'in' or 'local' here. */ restore /* cwp++ */ rdctl %o0 /* o0 <- status */ pfx %hi(0x7e00) movi %o1, %lo(0x7e00) not %o1 and %o0, %o1 /* clear IPRI */ pfx %hi(0x8600) movi %o1, %lo(0x8600) or %o0, %o1 /* IPRI=3, IE=1 */ wrctl %o0 /* o0 -> status */ nop /* It's ok to call a C routine now since cwp >= LO_LIMIT, * interrupt task's registers are/will be preserved, and * underflow exceptions can be handled. */ pfx %hi(external_interrupt@h) movi %o1, %lo(external_interrupt@h) pfx %xhi(external_interrupt@h) movhi %o1, %xlo(external_interrupt@h) bgen %o0, 4+2 /* 16 * 4 */ add %o0, %sp /* Ptr to regs */ call %o1 nop /* Move back to the exception register window, restore the 'out' * registers, then return from exception. */ rdctl %o0 /* o0 <- status */ subi %o0, 16 wrctl %o0 /* cwp-- */ nop mov %sp, %fp lds %g0, [%sp,16+0] /* Restore 'global' regs*/ lds %g1, [%sp,16+1] lds %g2, [%sp,16+2] lds %g3, [%sp,16+3] lds %g4, [%sp,16+4] lds %g5, [%sp,16+5] lds %g6, [%sp,16+6] lds %g7, [%sp,16+7] lds %i0, [%sp,16+8] /* Restore 'in' regs*/ lds %i1, [%sp,16+9] lds %i2, [%sp,16+10] lds %i3, [%sp,16+11] lds %i4, [%sp,16+12] lds %i5, [%sp,16+13] lds %i6, [%sp,16+14] lds %i7, [%sp,16+15] lds %l0, [%sp,16+16] /* status */ lds %l1, [%sp,16+17] /* istatus */ lds %o7, [%sp,16+18] /* return addr */ pfx 1 wrctl %l1 /* restore istatus */ pfx %hi((16+16+3) * 4) addi %sp, %lo((16+16+3) * 4) mov %fp, %sp tret %o7 /* Done */ /************************************************************************* * Timebase Timer Interrupt -- This has identical structure to above, * but calls timer_interrupt(). Doing it this way keeps things similar * to other architectures (e.g. ppc). ************************************************************************/ .text .global _timebase_int .align 4 _timebase_int: /* Allocate stack space. */ pfx %hi((16+16+3) * 4) subi %fp, %lo((16+16+3) * 4) mov %sp, %fp /* Save the 'global' regs & 'out' regs (our 'in' regs) */ rdctl %l0 /* status */ pfx 1 /* istatus */ rdctl %l1 sts [%sp,16+0], %g0 /* Save 'global' regs*/ sts [%sp,16+1], %g1 sts [%sp,16+2], %g2 sts [%sp,16+3], %g3 sts [%sp,16+4], %g4 sts [%sp,16+5], %g5 sts [%sp,16+6], %g6 sts [%sp,16+7], %g7 sts [%sp,16+8], %i0 /* Save 'in' regs */ sts [%sp,16+9], %i1 sts [%sp,16+10], %i2 sts [%sp,16+11], %i3 sts [%sp,16+12], %i4 sts [%sp,16+13], %i5 sts [%sp,16+14], %i6 sts [%sp,16+15], %i7 sts [%sp,16+16], %l0 /* status */ sts [%sp,16+17], %l1 /* istatus */ sts [%sp,16+18], %o7 /* return addr */ /* Move to cwp+1. */ restore /* cwp++ */ rdctl %o0 /* o0 <- status */ pfx %hi(0x7e00) movi %o1, %lo(0x7e00) not %o1 and %o0, %o1 /* clear IPRI */ pfx %hi(0x8600) movi %o1, %lo(0x8600) or %o0, %o1 /* IPRI=3, IE=1 */ wrctl %o0 /* o0 -> status */ nop /* Call timer_interrupt() */ pfx %hi(timer_interrupt@h) movi %o1, %lo(timer_interrupt@h) pfx %xhi(timer_interrupt@h) movhi %o1, %xlo(timer_interrupt@h) bgen %o0, 4+2 /* 16 * 4 */ add %o0, %sp /* Ptr to regs */ call %o1 nop /* Move back to the exception register window, restore the 'out' * registers, then return from exception. */ rdctl %o0 /* o0 <- status */ subi %o0, 16 wrctl %o0 /* cwp-- */ nop mov %sp, %fp lds %g0, [%sp,16+0] /* Restore 'global' regs*/ lds %g1, [%sp,16+1] lds %g2, [%sp,16+2] lds %g3, [%sp,16+3] lds %g4, [%sp,16+4] lds %g5, [%sp,16+5] lds %g6, [%sp,16+6] lds %g7, [%sp,16+7] lds %i0, [%sp,16+8] /* Restore 'in' regs*/ lds %i1, [%sp,16+9] lds %i2, [%sp,16+10] lds %i3, [%sp,16+11] lds %i4, [%sp,16+12] lds %i5, [%sp,16+13] lds %i6, [%sp,16+14] lds %i7, [%sp,16+15] lds %l0, [%sp,16+16] /* status */ lds %l1, [%sp,16+17] /* istatus */ lds %o7, [%sp,16+18] /* return addr */ pfx 1 wrctl %l1 /* restore istatus */ pfx %hi((16+16+3) * 4) addi %sp, %lo((16+16+3) * 4) mov %fp, %sp tret %o7 /* Done */ /************************************************************************* * GDB stubs ************************************************************************/ .text .global _brkpt_hw_int, _brkpt_sw_int .align 4 _brkpt_hw_int: movi %l1, 9 pfx 3 wrctl %l1 pfx 4 wrctl %l1 _brkpt_sw_int: movi %l1, 9 pfx 3 wrctl %l1 pfx 4 wrctl %l1 tret %o7