Fix brk system call.

This commit is contained in:
Michael Meissner 1995-09-06 14:00:16 +00:00
parent 49cb62cd75
commit c464ba6669
2 changed files with 42 additions and 15 deletions

View File

@ -312,24 +312,47 @@ core_stack_size(core *memory)
INLINE_CORE void INLINE_CORE void
core_add_data(core *memory, unsigned_word incr) core_add_data(core *memory, unsigned_word incr)
{ {
memory->data_upper_bound += incr; unsigned_word new_upper_bound = memory->data_upper_bound + incr;
if (memory->data_upper_bound > memory->data_high_water) { if (new_upper_bound > memory->data_high_water) {
malloc_core_memory(memory, memory->data_high_water, incr, if (memory->data_upper_bound >= memory->data_high_water)
/* all the memory is new */
malloc_core_memory(memory,
memory->data_upper_bound,
incr,
device_is_readable | device_is_writeable); device_is_readable | device_is_writeable);
memory->data_high_water = memory->data_upper_bound; else
/* some of the memory was already allocated, only need to add
missing bit */
malloc_core_memory(memory,
memory->data_high_water,
new_upper_bound - memory->data_high_water,
device_is_readable | device_is_writeable);
memory->data_high_water = new_upper_bound;
} }
memory->data_upper_bound = new_upper_bound;
} }
INLINE_CORE void INLINE_CORE void
core_add_stack(core *memory, unsigned_word incr) core_add_stack(core *memory, unsigned_word incr)
{ {
memory->stack_lower_bound -= incr; unsigned_word new_lower_bound = memory->stack_lower_bound - incr;
if (memory->stack_lower_bound < memory->stack_low_water) { if (new_lower_bound < memory->stack_low_water) {
malloc_core_memory(memory, memory->stack_lower_bound, incr, if (memory->stack_lower_bound <= memory->stack_low_water)
/* all the memory is new */
malloc_core_memory(memory,
new_lower_bound,
incr,
device_is_readable | device_is_writeable); device_is_readable | device_is_writeable);
memory->stack_low_water = memory->stack_lower_bound; else
/* allocate only the extra bit */
malloc_core_memory(memory,
new_lower_bound,
memory->stack_low_water - new_lower_bound,
device_is_readable | device_is_writeable);
memory->stack_low_water = new_lower_bound;
} }
memory->stack_lower_bound = new_lower_bound;
} }

View File

@ -169,13 +169,17 @@ system_call(cpu *processor,
# error "SYS_break" # error "SYS_break"
#endif #endif
{ {
unsigned_word new_sbrk = ALIGN_PAGE(cpu_registers(processor)->gpr[3]); /* pretend to extend the heap so that it reaches addresss
unsigned_word old_sbrk = core_data_upper_bound(cpu_core(processor)); new_break while in truth, if growth is needed grow it by a
signed_word delta = new_sbrk - old_sbrk; page aligned amount */
unsigned_word new_break = ALIGN_8(cpu_registers(processor)->gpr[3]);
unsigned_word old_break = core_data_upper_bound(cpu_core(processor));
signed_word delta = new_break - old_break;
if (delta > 0) if (delta > 0)
core_add_data(cpu_core(processor), delta); core_add_data(cpu_core(processor),
ALIGN_PAGE(new_break) - old_break);
cpu_registers(processor)->gpr[0] = 0; cpu_registers(processor)->gpr[0] = 0;
cpu_registers(processor)->gpr[3] = new_sbrk; cpu_registers(processor)->gpr[3] = new_break;
break; break;
} }