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Emit KEXC relocation table with -fauto-relocation #61

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Emit KEXC relocation table with -fauto-relocation #61

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53 changes: 15 additions & 38 deletions linker/linker.c
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Original file line number Diff line number Diff line change
Expand Up @@ -96,37 +96,15 @@ void resolve_immediate_values(list_t *symbols, area_t *area, list_t *errors) {
}

/* z80 only (and possibly ez80) */
void auto_relocate_area(area_t *area, area_t *runtime) {
void auto_relocate_area(area_t *area, area_t *relocation_table) {
scas_log(L_DEBUG, "Performing automatic relocation for %s", area->name);
uint8_t rst0x8 = 0xCF;
for (unsigned int i = 0; i < area->late_immediates->length; ++i) {
int i;
for (i = 0; i < area->late_immediates->length; ++i) {
late_immediate_t *imm = area->late_immediates->items[i];
if (imm->type != IMM_TYPE_RELATIVE) {
if (imm->base_address != imm->address) {
/* Relocate this */
scas_log(L_DEBUG, "Adding relocation instruction for immediate at 0x%08X (inserting at 0x%08X)", imm->address, imm->instruction_address);
insert_in_area(area, &rst0x8, sizeof(uint8_t), imm->instruction_address);
++imm->address;
/* Move everything that comes after */
for (unsigned k = 0; k < area->symbols->length; ++k) {
symbol_t *sym = area->symbols->items[k];
if (sym->type == SYMBOL_LABEL && sym->value > imm->instruction_address) {
++sym->value;
}
}
for (unsigned int j = 0; j < area->late_immediates->length; ++j) {
late_immediate_t *_imm = area->late_immediates->items[j];
if (_imm->base_address > imm->base_address) {
++_imm->base_address;
++_imm->instruction_address;
++_imm->address;
}
}
} else {
/* Relocate this */
uint16_t value = (uint16_t)(imm->address + area->final_address);
append_to_area(runtime, (uint8_t*)&value, sizeof(uint16_t));
}
if (imm->type != IMM_TYPE_RELATIVE && imm->base_address != imm->address) {
/* Relocate this */
uint16_t value = (uint16_t)(imm->address + area->final_address);
append_to_area(relocation_table, (uint8_t*)&value, sizeof(uint16_t));
}
}
}
Expand Down Expand Up @@ -154,19 +132,18 @@ void link_objects(FILE *output, list_t *objects, linker_settings_t *settings) {
list_t *symbols = create_list(); // TODO: Use a hash table

/* Create a new area for relocatable references */
area_t *runtime = NULL;
area_t *relocation_table;
if (settings->automatic_relocation) {
const char *sym_name = "__scas_relocatable_data";
runtime = create_area("__scas_relocatable");
relocation_table = create_area("__scas_relocation_table");
symbol_t *sym = malloc(sizeof(symbol_t));
sym->type = SYMBOL_LABEL;
sym->name = strdup(sym_name);
sym->name = strdup("__scas_relocation_table");
sym->value = 0;
sym->defined_address = 0;
sym->exported = 0;
list_add(runtime->symbols, sym);
list_add(relocation_table->symbols, sym);
object_t *o = create_object();
list_add(o->areas, runtime);
list_add(o->areas, relocation_table);
list_add(objects, o);
}

Expand All @@ -178,7 +155,7 @@ void link_objects(FILE *output, list_t *objects, linker_settings_t *settings) {

area_t *final = create_area("FINAL");

runtime = get_area_by_name(merged, "__scas_relocatable");
relocation_table = get_area_by_name(merged, "__scas_relocation_table");

scas_log(L_INFO, "Assigning final address for all areas");
if (scas_runtime.options.remove_unused_functions) {
Expand All @@ -189,11 +166,11 @@ void link_objects(FILE *output, list_t *objects, linker_settings_t *settings) {
area_t *area = merged->areas->items[i];
relocate_area(area, address, false);
if (settings->automatic_relocation) {
if (area == runtime) {
if (area == relocation_table) {
uint16_t null_ptr = 0;
append_to_area(area, (uint8_t *)&null_ptr, sizeof(uint16_t));
} else {
auto_relocate_area(area, runtime);
auto_relocate_area(area, relocation_table);
}
}
address += area->data_length;
Expand Down