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be-func-z80.c
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be-func-z80.c
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/*
* General backend helpers for Z80 except for code generator
*/
#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include "compiler.h"
#include "backend.h"
#include "backend-z80.h"
/* Export the C symbol */
void gen_export(const char *name)
{
printf(" .export _%s\n", name);
}
void gen_segment(unsigned segment)
{
switch(segment) {
case A_CODE:
printf("\t.%s\n", codeseg);
break;
case A_DATA:
printf("\t.data\n");
break;
case A_BSS:
printf("\t.bss\n");
break;
case A_LITERAL:
printf("\t.literal\n");
break;
default:
error("gseg");
}
}
/* Generate the function prologue - may want to defer this until
gen_frame for the most part */
void gen_prologue(const char *name)
{
printf("_%s:\n", name);
unreachable = 0;
}
/* Generate the stack frame */
/* TODO: defer this to statements so we can ld/push initializers */
void gen_frame(unsigned size, unsigned aframe)
{
frame_len = size;
sp = 0;
use_fp = 0;
if (size || (func_flags & (F_REG(1)|F_REG(2)|F_REG(3))))
func_cleanup = 1;
else
func_cleanup = 0;
argbase = ARGBASE;
/* In banked mode the arguments are two bytes further out */
if (cpufeat & 1)
argbase += 2;
if (func_flags & F_REG(1)) {
printf("\tpush bc\n");
argbase += 2;
}
if (func_flags & F_REG(2)) {
printf("\tpush ix\n");
argbase += 2;
}
if (func_flags & F_REG(3)) {
printf("\tpush iy\n");
argbase += 2;
} else {
/* IY is free use it as a frame pointer ? */
if (!optsize && size > 4) {
argbase += 2;
printf("\tpush iy\n");
/* Remember we need to restore IY */
func_flags |= F_REG(3);
use_fp = 1;
}
}
/* If we are building a frame pointer we need to do this work anyway */
if (use_fp) {
printf("\tld iy,0x%x\n", (uint16_t) - size);
printf("\tadd iy,sp\n");
printf("\tld sp,iy\n");
return;
}
if (size > 10) {
printf("\tld hl,0x%x\n", (uint16_t) -size);
printf("\tadd hl,sp\n");
printf("\tld sp,hl\n");
return;
}
if (size & 1) {
printf("\tdec sp\n");
size--;
}
while(size) {
printf("\tpush hl\n");
size -= 2;
}
}
void gen_epilogue(register unsigned size, unsigned argsize)
{
if (sp != 0)
error("sp");
/* Return in HL, does need care on stack. TOOD: flag void functions
where we can burn the return */
sp -= size;
/* This can happen if the function never returns or the only return
is a by a ret directly (ie from a function without locals) */
if (unreachable)
return;
if (size > 10) {
unsigned x = func_flags & F_VOIDRET;
if (!x)
printf("\tex de,hl\n");
printf("\tld hl,0x%x\n", (uint16_t)size);
printf("\tadd hl,sp\n");
printf("\tld sp,hl\n");
if (!x)
printf("\tex de,hl\n");
} else {
if (size & 1) {
printf("\tinc sp\n");
size--;
}
while (size) {
printf("\tpop de\n");
size -= 2;
}
}
if (func_flags & F_REG(3))
printf("\tpop iy\n");
if (func_flags & F_REG(2))
printf("\tpop ix\n");
if (func_flags & F_REG(1))
printf("\tpop bc\n");
printf("\tret\n");
unreachable = 1;
}
void gen_label(const char *tail, unsigned n)
{
unreachable = 0;
printf("L%u%s:\n", n, tail);
}
/* A return statement. We can sometimes shortcut this if we have
no cleanup to do */
unsigned gen_exit(const char *tail, unsigned n)
{
if (func_cleanup) {
gen_jump(tail, n);
return 0;
} else {
printf("\tret\n");
unreachable = 1;
return 1;
}
}
void gen_jump(const char *tail, unsigned n)
{
printf("\tjr L%u%s\n", n, tail);
unreachable = 1;
}
void gen_jfalse(const char *tail, unsigned n)
{
printf("\tjr %s,L%u%s\n", ccflags + 2, n, tail);
ccflags = ccnormal;
}
void gen_jtrue(const char *tail, unsigned n)
{
printf("\tjr %c%c,L%u%s\n", ccflags[0], ccflags[1], n, tail);
ccflags = ccnormal;
}
void gen_cleanup(register unsigned v)
{
/* CLEANUP is special and needs to be handled directly */
sp -= v;
if (v > 10) {
/* This is more expensive, but we don't often pass that many
arguments so it seems a win to stay in HL */
/* TODO: spot void function and skip ex de,hl */
printf("\tex de,hl\n");
printf("\tld hl,0x%x\n", v);
printf("\tadd hl,sp\n");
printf("\tld sp,hl\n");
printf("\tex de,hl\n");
} else {
while(v >= 2) {
printf("\tpop de\n");
v -= 2;
}
if (v)
printf("\tinc sp\n");
}
}
/*
* Helper handlers. We use a tight format for integers but C
* style for float as we'll have C coded float support if any
*/
/* True if the helper is to be called C style */
static unsigned c_style(register struct node *n)
{
/* Assignment is done asm style */
if (n->op == T_EQ)
return 0;
/* Float ops otherwise are C style */
if (n->type == FLOAT)
return 1;
n = n->right;
if (n && n->type == FLOAT)
return 1;
return 0;
}
void gen_helpcall(struct node *n)
{
/* Check both N and right because we handle casts to/from float in
C call format */
if (c_style(n))
gen_push(n->right);
printf("\tcall __");
}
void gen_helptail(struct node *n)
{
}
void gen_helpclean(register struct node *n)
{
register unsigned s;
if (c_style(n)) {
s = 0;
if (n->left) {
s += get_size(n->left->type);
/* gen_node already accounted for removing this thinking
the helper did the work, adjust it back as we didn't */
sp += s;
}
s += get_size(n->right->type);
gen_cleanup(s);
/* C style ops that are ISBOOL didn't set the bool flags */
if (n->flags & ISBOOL)
printf("\txor a\n\tcp l\n");
}
}
void gen_switch(unsigned n, unsigned type)
{
printf("\tld de,Sw%u\n", n);
printf("\tjp __switch");
helper_type(type, 0);
printf("\n");
unreachable = 1;
}
void gen_switchdata(unsigned n, unsigned size)
{
printf("Sw%u:\n", n);
printf("\t.word %u\n", size);
}
void gen_case_label(unsigned tag, unsigned entry)
{
unreachable = 0;
printf("Sw%u_%u:\n", tag, entry);
}
void gen_case_data(unsigned tag, unsigned entry)
{
printf("\t.word Sw%u_%u\n", tag, entry);
}
void gen_data_label(const char *name, unsigned align)
{
printf("_%s:\n", name);
}
void gen_space(unsigned value)
{
printf("\t.ds %u\n", value);
}
void gen_text_data(struct node *n)
{
printf("\t.word T%u\n", n->val2);
}
/* The label for a literal (currently only strings)
TODO: if we add other literals we may need alignment here */
void gen_literal(unsigned n)
{
if (n)
printf("T%u:\n", n);
}
void gen_name(struct node *n)
{
printf("\t.word _%s+%u\n", namestr(n->snum), WORD(n->value));
}
void gen_value(unsigned type, unsigned long value)
{
unsigned w = WORD(value);
if (PTR(type)) {
printf("\t.word %u\n", w);
return;
}
switch (type) {
case CCHAR:
case UCHAR:
printf("\t.byte %u\n", BYTE(w));
break;
case CSHORT:
case USHORT:
printf("\t.word %u\n", w);
break;
case CLONG:
case ULONG:
case FLOAT:
/* We are little endian */
printf("\t.word %u\n", w);
printf("\t.word %u\n", (unsigned) ((value >> 16) & 0xFFFF));
break;
default:
error("unsuported type");
}
}
void gen_start(void)
{
/* For now.. */
printf("\t.z80\n");
}
void gen_end(void)
{
}