From 7786d06f1866aadcbd3a077b6f1408fd2728a0bd Mon Sep 17 00:00:00 2001
From: Tucker Evans <tuckerevans24@gmail.com>
Date: Wed, 9 Oct 2019 06:57:47 -0400
Subject: Add Stack save/load routines

---
 gen_code.c | 40 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 40 insertions(+)

diff --git a/gen_code.c b/gen_code.c
index 2e21244..41e9113 100644
--- a/gen_code.c
+++ b/gen_code.c
@@ -24,6 +24,42 @@ scope *cur_scope;
 char **reg_stack, **reg_ptr;
 int reg_cnt;
 
+#define STACK_SAVE {\
+	fprintf(stdout,
+	"pushq\t%rax\n"\
+	"pushq\t%rcx\n"\
+	"pushq\t%rdx\n"\
+	"pushq\t%rsi\n"\
+	"pushq\t%rdi\n"\
+	"pushq\tr8\n"  \
+	"pushq\tr9\n"  \
+	"pushq\t%r10\n"\
+	"pushq\t%r11\n"\
+	"pushq\t%r12\n"\
+	"pushq\t%r13\n"\
+	"pushq\t%r14\n"\
+	"pushq\t%r15\n"\
+	)\
+}
+
+#define STACK_LOAD {\
+	fprintf(stdout,
+	"popq\t%r15\n"\
+	"popq\t%r14\n"\
+	"popq\t%r13\n"\
+	"popq\t%r12\n"\
+	"popq\t%r11\n"\
+	"popq\t%r10\n"\
+	"popq\tr9\n"  \
+	"popq\tr8\n"  \
+	"popq\t%rdi\n"\
+	"popq\t%rsi\n"\
+	"popq\t%rdx\n"\
+	"popq\t%rcx\n"\
+	"popq\t%rax\n"\
+	)\
+}
+
 int gen_label(t)
 ptree *t;
 {
@@ -178,21 +214,25 @@ ptree *t;
 		if (!strcmp(t->l->attr.nval->name, "write")) {
 			GEN_EXPR(t->r);
 			fprintf(stdout, "movq %s, %%rsi\n", *reg_ptr);
+			STACK_SAVE
 			fprintf(stdout, "leaq int_print(%%rip),"
 					"%%rdi\n");
 			fprintf(stdout, "movq $0, %%rax\n");
 			fprintf(stdout, "call printf\n");
+			STACK_LOAD
 			break;
 		} else if (!strcmp(t->l->attr.nval->name, "read")) {
 			fprintf(stderr,"Read\n");
 			break;
 		}
 
+		STACK_SAVE
 		fprintf(stdout, "subq $%d, %%rsp\n", 
 				t->l->attr.nval->func_info->argc * OFFSET_SIZE);
 		gen_arguments(t->r);
 
 		fprintf(stdout, "call\t%s\n", t->l->attr.nval->name);
+		STACK_LOAD
 
 
 		break;
-- 
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