From: Luke Lau <luke.lau@intel.com>
Date: Wed, 24 Jul 2019 13:29:45 +0000 (+0100)
Subject: Fix string addressing and clobbered register
X-Git-Url: http://git.lukelau.me/?p=scheme.git;a=commitdiff_plain;h=dea4c4e4d1be8c0a90bb165bde1e362dc204e061

Fix string addressing and clobbered register
---

diff --git a/codegen.scm b/codegen.scm
index 25d99a1..4848d4d 100644
--- a/codegen.scm
+++ b/codegen.scm
@@ -50,6 +50,9 @@
 (define (codegen-print x si env)
   (codegen-expr x si env) ; x should be a static-string, producing a label
 
+		      ; make a copy of string address since %rax and %rdi are clobbered
+  (emit "mov %rax, %rbx")
+  
 		      ; get the length of the null terminated string
   (emit "mov %rax, %rdi")
   (emit "xor %al, %al")   ; set %al to 0
@@ -61,7 +64,7 @@
   (emit "dec %rcx")
   
   (emit "mov %rcx, %rdx") ; number of bytes
-  (emit "mov %rax, %rsi") ; addr of string
+  (emit "mov %rbx, %rsi") ; addr of string
   (emit "mov $1, %rax") ; file handle 1 (stdout)
   (emit "mov $1, %rdi") ; syscall 1 (write)
   (emit "syscall"))
@@ -213,7 +216,7 @@
     ('bool-literal (emit "movq $~a, %rax" (if e 1 0)))
     ('int-literal (emit "movq $~a, %rax" e))
     
-    ('static-string (emit "movq (~a), %rax" (cadr e))) ; move label
+    ('static-string (emit "lea ~a, %rax" (cadr e))) ; move label
 
     (else (error #f "don't know how to codegen this"))))