int asm_invert(ulong *res, ulong *b) /* inverts b mod N */
{
long i, f1, len;
ulong t1[NMAX_ULONGS], t2[NMAX_ULONGS];
ulong v1[NMAX_ULONGS], v2[NMAX_ULONGS];
ulong n_half[NMAX_ULONGS];
for (i=0; i<montgomery_ulongs; i++) if (b[i]) break;
if (i>=montgomery_ulongs) return 0;
if (b[0]&1) {
asm_copy(t1,b); f1=0;
} else {
asm_sub(t1,montgomery_modulo_n,b); f1=1;
}
asm_zero(t2); t2[0]=1;
asm_copy(v1,montgomery_modulo_n); asm_zero(v2);
len=montgomery_ulongs-1;
while (1) {
if (!(t1[len]|v1[len])) len--;
for (i=len; i>=0; i--) if (t1[i]!=v1[i]) break;
if (i<0) break;
if (t1[i]>v1[i]) { /* t1>v1 */
asm_sub_n(t1,v1); /* t1 even */
asm_sub(t2,t2,v2);
do {
for (i=0; i<len; i++) t1[i]=(t1[i]>>1)|(t1[i+1]<<31);
t1[len]>>=1;
asm_half(t2);
} while (!(t1[0]&1));
} else { /* v1>t1 */
static void gen_func_dec(ClmStmtNode *node) {
int i;
char func_label[LABEL_SIZE];
sprintf(func_label, "_%s", node->funcDecStmt.name);
ClmScope *funcScope = clm_scope_find_child(data.scope, node);
asm_label(func_label);
asm_push(EBP);
asm_mov(EBP, ESP);
int local_var_size = 2 * 4 * (funcScope->symbols->length -
node->funcDecStmt.parameters->length);
char local_var_size_str[32];
sprintf(local_var_size_str, "%d", local_var_size);
asm_sub(ESP, local_var_size_str);
// each local var has 2 slots on the stack, their type and the value
// for matrices, the value is a pointer to the location on the stack
// these are all declared below the local variables
ClmSymbol *sym;
ClmExpNode *dec;
char cmp_label[LABEL_SIZE];
char end_label[LABEL_SIZE];
char index_str[32];
for (i = 0; i < funcScope->symbols->length; i++) {
sym = funcScope->symbols->data[i];
dec = sym->declaration;
if (sym->location == LOCATION_PARAMETER)
continue;
// setting the type of the local var
load_var_location(sym, index_str, 0, NULL);
asm_mov_i(index_str, (int)sym->type);
// setting the value of the local var
load_var_location(sym, index_str, 4, NULL);
asm_mov_i(index_str, 0);
if (sym->type == CLM_TYPE_MATRIX) {
// TODO what does this do? does it work?
next_label(cmp_label);
next_label(end_label);
gen_exp_size(dec);
asm_pop(EAX); // eax contains num of rows
asm_pop(EBX); // ebx contains num of cols
asm_mov(ECX, EAX);
asm_imul(ECX, EBX);
asm_label(cmp_label);
asm_dec(ECX);
asm_cmp(ECX, "0");
asm_jmp_eq(end_label);
asm_push_const_i(0);
asm_jmp(cmp_label);
asm_label(end_label);
asm_push(EBX); // cols
// setting the pointer to point at the rows
// note: push changes the value at esp and THEN
// decrements it
load_var_location(sym, index_str, 4, NULL);
asm_mov(index_str, ESP);
asm_push(EAX); // rows
}
}
// TODO figure out strings though!
data.inFunction = 1;
data.scope = funcScope;
gen_statements(node->funcDecStmt.body);
data.scope = funcScope->parent;
data.inFunction = 0;
if (node->funcDecStmt.returnSize.rows == -1) {
// no return value!
asm_mov(ESP, EBP);
asm_pop(EBP);
}
asm_ret();
}