nctref/src/x86.h

#pragma once

#include<string.h>
#include"ntc.h"
#include<assert.h>

#define COLOR_EAX 0
#define COLOR_ECX 1
#define COLOR_EDX 2
#define COLOR_EBX 3

// Can expression be expressed as a single x86 operand?
#define XOP_NOT_XOP 0
#define XOP_NOT_MEM 1
#define XOP_MEM 2
static inline int is_xop(AST *e) {
	if(e->nodeKind == AST_EXPR_CAST && e->exprCast.what->expression.type->type == TYPE_TYPE_POINTER && e->exprCast.to->type == TYPE_TYPE_POINTER) {
		e = e->exprCast.what;
	}
	
	if(e->nodeKind == AST_EXPR_PRIMITIVE) {
		return XOP_NOT_MEM;
	} else if(e->nodeKind == AST_EXPR_VAR) {
		return e->exprVar.thing->kind == VARTABLEENTRY_VAR ? XOP_NOT_MEM : XOP_MEM;
	} else if(e->nodeKind == AST_EXPR_UNARY_OP && e->exprUnOp.operator == UNOP_DEREF && e->exprUnOp.operand->nodeKind == AST_EXPR_BINARY_OP && e->exprUnOp.operand->exprBinOp.operator == BINOP_ADD && is_xop(e->exprUnOp.operand->exprBinOp.operands[0]) == XOP_NOT_MEM && is_xop(e->exprUnOp.operand->exprBinOp.operands[1]) == XOP_NOT_MEM) {
		return XOP_MEM;
	} else if(e->nodeKind == AST_EXPR_UNARY_OP && e->exprUnOp.operator == UNOP_REF && e->exprUnOp.operand->nodeKind == AST_EXPR_VAR && e->exprUnOp.operand->exprVar.thing->kind == VARTABLEENTRY_SYMBOL) {
		return XOP_NOT_MEM;
	} else if(e->nodeKind == AST_EXPR_UNARY_OP && e->exprUnOp.operator == UNOP_DEREF) {
		AST *c = e->exprUnOp.operand;
		
		if(c->nodeKind == AST_EXPR_CAST && c->exprCast.what->expression.type->type == TYPE_TYPE_POINTER && c->exprCast.to->type == TYPE_TYPE_POINTER) {
			c = c->exprCast.what;
		}
		
		if(c->nodeKind == AST_EXPR_VAR && c->exprVar.thing->kind == VARTABLEENTRY_VAR) {
			return XOP_MEM;
		} else if(
			(c->nodeKind == AST_EXPR_BINARY_OP && c->exprBinOp.operator == BINOP_ADD && c->exprBinOp.operands[0]->nodeKind == AST_EXPR_UNARY_OP && c->exprBinOp.operands[0]->exprUnOp.operator == UNOP_REF && c->exprBinOp.operands[0]->exprUnOp.operand->nodeKind == AST_EXPR_VAR) || 
			(c->nodeKind == AST_EXPR_BINARY_OP && c->exprBinOp.operator == BINOP_ADD && c->exprBinOp.operands[0]->nodeKind == AST_EXPR_VAR)) {
			
			if(c->exprBinOp.operands[1]->nodeKind == AST_EXPR_PRIMITIVE) {
				return XOP_MEM;
			} else if(c->exprBinOp.operands[1]->nodeKind == AST_EXPR_VAR) {
				return XOP_MEM;
			} else if(c->exprBinOp.operands[1]->nodeKind == AST_EXPR_BINARY_OP && c->exprBinOp.operands[1]->exprBinOp.operator == BINOP_MUL && c->exprBinOp.operands[1]->exprBinOp.operands[0]->nodeKind == AST_EXPR_PRIMITIVE && c->exprBinOp.operands[1]->exprBinOp.operands[1]->nodeKind == AST_EXPR_VAR) {
				int scale = c->exprBinOp.operands[1]->exprBinOp.operands[0]->exprPrim.val;
				
				if(scale == 1 || scale == 2 || scale == 4 || scale == 8) {
					return XOP_MEM;
				}
			}
		}
	} else if(e->nodeKind == AST_EXPR_STACK_POINTER) {
		return XOP_NOT_MEM;
	}
	
	return XOP_NOT_XOP;
}

typedef enum {
	NOT_AT_ALL_IT,
	DEST_IS_BAD_XOP,
	SRC0_IS_BAD_XOP,
	SRC1_IS_BAD_XOP,
	DEST_NOT_PRECOLORED,
	SRC0_NOT_PRECOLORED,
	SRC1_NOT_PRECOLORED,
	DEST_NOT_SRC0,
	MISSING_MULHI_FOR_MUL,
	GUCCI,
} WhysItBad_Huh;

typedef enum {
	I086 = 0,
	I186 = 1,
	I286 = 2,
	I386 = 3,
	IUNKNOWN86 = 255,
} X86Target;

static inline X86Target x86_target() {
	const char *str = ntc_get_arg("target");
	
	if(!str) return I386;
	
	if(!strcmp(str, "086")) {
		return I086;
	}
	
	if(!strcmp(str, "186")) {
		return I186;
	}
	
	if(!strcmp(str, "286")) {
		return I286;
	}
	
	if(!strcmp(str, "386")) {
		return I386;
	}
	
	return IUNKNOWN86;
}

static inline size_t x86_max_gpr_size() {
	switch(x86_target()) {
	case I086:
	case I186:
	case I286:
		return 2;
	case I386:
		return 4;
	default: abort();
	}
}

static inline bool x86_imul_supported() {
	return x86_target() >= I186;
}

static inline WhysItBad_Huh x86_test_mul_matching_mulhi(AST *mulhi, AST *mul) {
	assert(mulhi->statement.next == mul);
	
	if(mulhi->stmtAssign.to->nodeKind != AST_EXPR_BINARY_OP) {
		return NOT_AT_ALL_IT;
	}
	
	if(mulhi->stmtAssign.to->exprBinOp.operator != BINOP_MULHI) {
		return NOT_AT_ALL_IT;
	}
	
	if(!ast_expression_equal(mulhi->stmtAssign.to->exprBinOp.operands[0], mul->stmtAssign.to->exprBinOp.operands[0])) {
		return NOT_AT_ALL_IT;
	}
	
	if(!ast_expression_equal(mulhi->stmtAssign.to->exprBinOp.operands[1], mul->stmtAssign.to->exprBinOp.operands[1])) {
		return NOT_AT_ALL_IT;
	}
	
	if(is_xop(mulhi->stmtAssign.what) != XOP_NOT_MEM) {
		return DEST_IS_BAD_XOP;
	}
	
	return GUCCI;
}

static inline WhysItBad_Huh x86_test_mul(AST *stmtPrev, AST *stmt) {
	if(stmt->nodeKind != AST_STMT_ASSIGN) {
		return NOT_AT_ALL_IT;
	}
	
	if(stmt->stmtAssign.to->nodeKind != AST_EXPR_BINARY_OP) {
		return NOT_AT_ALL_IT;
	}
	
	if(stmt->stmtAssign.to->exprBinOp.operator != BINOP_MUL) {
		return NOT_AT_ALL_IT;
	}
	
	if(stmt->stmtAssign.what->nodeKind != AST_EXPR_VAR || stmt->stmtAssign.what->exprVar.thing->kind != VARTABLEENTRY_VAR) {
		return DEST_IS_BAD_XOP;
	}
	
	if(x86_imul_supported()) {
		return GUCCI;
	} else if(stmt->stmtAssign.to->exprBinOp.operands[1]->nodeKind == AST_EXPR_PRIMITIVE) {
		return SRC1_IS_BAD_XOP;
	}
	
	if(is_xop(stmt->stmtAssign.to->exprBinOp.operands[1]) == XOP_NOT_XOP) {
		return SRC1_IS_BAD_XOP;
	}
	
	/*if(stmt->stmtAssign.to->exprBinOp.operands[1]->nodeKind == AST_EXPR_PRIMITIVE && x86_get_target() < I186) {
		return SRC1_IS_BAD_XOP;
	}*/
	
	if(!ast_expression_equal(stmt->stmtAssign.what, stmt->stmtAssign.to->exprBinOp.operands[0])) {
		return DEST_NOT_SRC0;
	}
	
	if(!stmt->stmtAssign.what->exprVar.thing->data.var.precolored) {
		return DEST_NOT_PRECOLORED;
	}
	
	if(x86_test_mul_matching_mulhi(stmtPrev, stmt) != GUCCI) {
		return MISSING_MULHI_FOR_MUL;
	}
	
	return GUCCI;
}