diff options
Diffstat (limited to 'erts')
| -rw-r--r-- | erts/emulator/beam/global.h | 61 | ||||
| -rw-r--r-- | erts/emulator/beam/utils.c | 26 |
2 files changed, 87 insertions, 0 deletions
diff --git a/erts/emulator/beam/global.h b/erts/emulator/beam/global.h index dcba8bbba8..09f43348f4 100644 --- a/erts/emulator/beam/global.h +++ b/erts/emulator/beam/global.h @@ -685,6 +685,67 @@ do { \ #define WSTACK_POP(s) ((ASSERT(s.wsp > s.wstart)),*(--s.wsp)) + +/* PSTACK - Stack of any type. + * Usage: + * { + * #define PSTACK_TYPE MyType + * PSTACK_DECLARE(s,16); + * MyType *sp = PSTACK_PUSH(s); + * + * sp->x = .... + * sp->y = .... + * sp = PSTACK_PUSH(s); + * ... + * sp = PSTACK_POP(s); + * if (PSTACK_IS_EMPTY(s)) { + * // sp is invalid when stack is empty after pop + * } + * + * PSTACK_DESTROY(s); + * } + */ + + +typedef struct ErtsPStack_ { + byte* pstart; + byte* psp; + byte* pend; + ErtsAlcType_t alloc_type; +}ErtsPStack; + +void erl_grow_pstack(ErtsPStack* s, void* default_pstack, unsigned need_bytes); +#define PSTK_CONCAT(a,b) a##b +#define PSTK_DEF_STACK(s) PSTK_CONCAT(s,_default_pstack) + +#define PSTACK_DECLARE(s, DEF_PSTACK_SIZE) \ +PSTACK_TYPE PSTK_DEF_STACK(s)[DEF_PSTACK_SIZE]; \ +ErtsPStack s = { (byte*)PSTK_DEF_STACK(s), /* pstart */ \ + (byte*)(PSTK_DEF_STACK(s) - 1), /* psp */ \ + (byte*)(PSTK_DEF_STACK(s) + (DEF_PSTACK_SIZE)), /* pend */\ + ERTS_ALC_T_ESTACK /* alloc_type */ \ +} + +#define PSTACK_DESTROY(s) \ +do { \ + if (s.pstart != (byte*)PSTK_DEF_STACK(s)) { \ + erts_free(s.alloc_type, s.pstart); \ + } \ +} while(0) + +#define PSTACK_IS_EMPTY(s) (s.psp < s.pstart) + +#define PSTACK_TOP(s) (ASSERT(!PSTACK_IS_EMPTY(s)), (PSTACK_TYPE*)(s.psp)) + +#define PSTACK_PUSH(s) \ + (s.psp += sizeof(PSTACK_TYPE), \ + ((s.psp == s.pend) ? erl_grow_pstack(&s, PSTK_DEF_STACK(s), \ + sizeof(PSTACK_TYPE)) : (void)0), \ + ((PSTACK_TYPE*) s.psp)) + +#define PSTACK_POP(s) ((PSTACK_TYPE*) (s.psp -= sizeof(PSTACK_TYPE))) + + /* binary.c */ void erts_emasculate_writable_binary(ProcBin* pb); diff --git a/erts/emulator/beam/utils.c b/erts/emulator/beam/utils.c index bd90ec2fba..a54a93b086 100644 --- a/erts/emulator/beam/utils.c +++ b/erts/emulator/beam/utils.c @@ -239,6 +239,32 @@ erl_grow_wstack(ErtsWStack* s, UWord* default_wstack, Uint need) s->wsp = s->wstart + sp_offs; } +/* + * Helper function for the PSTACK macros defined in global.h. + */ +void +erl_grow_pstack(ErtsPStack* s, void* default_pstack, unsigned need_bytes) +{ + Uint old_size = s->pend - s->pstart; + Uint new_size; + Uint sp_offs = s->psp - s->pstart; + + if (need_bytes < old_size) + new_size = 2 * old_size; + else + new_size = ((need_bytes / old_size) + 2) * old_size; + + if (s->pstart != default_pstack) { + s->pstart = erts_realloc(s->alloc_type, s->pstart, new_size); + } else { + byte* new_ptr = erts_alloc(s->alloc_type, new_size); + sys_memcpy(new_ptr, s->pstart, old_size); + s->pstart = new_ptr; + } + s->pend = s->pstart + new_size; + s->psp = s->pstart + sp_offs; +} + /* CTYPE macros */ #define LATIN1 |