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/*******************************************************
* ------------------------------------------------- *
* | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | *
* ------------------------------------------------- *
* | 0 | 8 | 16 | 24 | *
* ------------------------------------------------- *
* | t.fctx | t.data | r2 | r6 | *
* ------------------------------------------------- *
* ------------------------------------------------- *
* | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | *
* ------------------------------------------------- *
* | 32 | 40 | 48 | 56 | *
* ------------------------------------------------- *
* | r7 | r8 | r9 | r10 | *
* ------------------------------------------------- *
* ------------------------------------------------- *
* | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | *
* ------------------------------------------------- *
* | 64 | 72 | 80 | 88 | *
* ------------------------------------------------- *
* | r11 | r12 | r13 | r14 | *
* ------------------------------------------------- *
* ------------------------------------------------- *
* | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | *
* ------------------------------------------------- *
* | 96 | 104 | 112 | 120 | *
* ------------------------------------------------- *
* | f8 | f9 | f10 | f11 | *
* ------------------------------------------------- *
* ------------------------------------------------- *
* | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39 | *
* ------------------------------------------------- *
* | 128 | 136 | 144 | 152 | *
* ------------------------------------------------- *
* | f12 | f13 | f14 | f15 | *
* ------------------------------------------------- *
* ------------------------------------------------- *
* | 40 | 41 | 42 | 43 | 44 | 45 | 46 | 47 | *
* ------------------------------------------------- *
* | 160 | 168 | 176 | | *
* ------------------------------------------------- *
* | fpc | pc | | | *
* ------------------------------------------------- *
*******************************************************/
.text
.align 8
.global jump_fcontext
.type jump_fcontext, @function
#define ARG_OFFSET 0
#define GR_OFFSET 16
#define FP_OFFSET 96
#define FPC_OFFSET 160
#define PC_OFFSET 168
#define CONTEXT_SIZE 176
#define REG_SAVE_AREA_SIZE 160
/*
typedef void* fcontext_t;
struct transfer_t {
fcontext_t fctx;
void * data;
};
transfer_t jump_fcontext( fcontext_t const to,
void * data);
Incoming args
r2 - Hidden argument to the location where the return transfer_t needs to be returned
r3 - Context we want to switch to
r4 - Data pointer
*/
jump_fcontext:
.machine "z10"
/* Reserve stack space to store the current context. */
aghi %r15,-CONTEXT_SIZE
/* Save the argument register holding the location of the return value. */
stg %r2,GR_OFFSET(%r15)
/* Save the call-saved general purpose registers. */
stmg %r6,%r14,GR_OFFSET+8(%r15)
/* Save call-saved floating point registers. */
std %f8,FP_OFFSET(%r15)
std %f9,FP_OFFSET+8(%r15)
std %f10,FP_OFFSET+16(%r15)
std %f11,FP_OFFSET+24(%r15)
std %f12,FP_OFFSET+32(%r15)
std %f13,FP_OFFSET+40(%r15)
std %f14,FP_OFFSET+48(%r15)
std %f15,FP_OFFSET+56(%r15)
/* Save the return address as current pc. */
stg %r14,PC_OFFSET(%r15)
/* Save the floating point control register. */
stfpc FPC_OFFSET(%r15)
/* Backup the stack pointer pointing to the old context-data into r1. */
lgr %r1,%r15
/* Load the new context pointer as stack pointer. */
lgr %r15,%r3
/* Restore the call-saved GPRs from the new context. */
lmg %r6,%r14,GR_OFFSET+8(%r15)
/* Restore call-saved floating point registers. */
ld %f8,FP_OFFSET(%r15)
ld %f9,FP_OFFSET+8(%r15)
ld %f10,FP_OFFSET+16(%r15)
ld %f11,FP_OFFSET+24(%r15)
ld %f12,FP_OFFSET+32(%r15)
ld %f13,FP_OFFSET+40(%r15)
ld %f14,FP_OFFSET+48(%r15)
ld %f15,FP_OFFSET+56(%r15)
/* Load the floating point control register. */
lfpc FPC_OFFSET(%r15)
/* Restore PC - the location where we will jump to at the end. */
lg %r5,PC_OFFSET(%r15)
ltg %r2,GR_OFFSET(%r15)
jnz use_return_slot
/* We restore a make_fcontext context. Use the function
argument slot in the context we just saved and allocate the
register save area for the target function. */
la %r2,ARG_OFFSET(%r1)
aghi %r15,-REG_SAVE_AREA_SIZE
use_return_slot:
/* Save the two fields in transfer_t. When calling a
make_fcontext function this becomes the function argument of
the target function, otherwise it will be the return value of
jump_fcontext. */
stg %r1,0(%r2)
stg %r4,8(%r2)
/* Free the restored context. */
aghi %r15,CONTEXT_SIZE
/* Jump to the PC loaded from the new context. */
br %r5
.size jump_fcontext,.-jump_fcontext
.section .note.GNU-stack,"",%progbits
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