Notizen und Beispiele 31.5.2022

20220531/variables-01.c

+#include <stdint.h>
+
+uint8_t x = 3;
+
+int main (void)
+{
+  x = 7;
+  return 1;
+}

20220531/variables-01.s

+	.file	"variables-01.c"
+__SP_H__ = 0x3e
+__SP_L__ = 0x3d
+__SREG__ = 0x3f
+__tmp_reg__ = 0
+__zero_reg__ = 1
+	.section	.text.startup,"ax",@progbits
+.global	main
+	.type	main, @function
+main:
+/* prologue: function */
+/* frame size = 0 */
+/* stack size = 0 */
+.L__stack_usage = 0                              ; #include <stdint.h>
+	ldi r24,lo8(7)                           ; 
+	sts x,r24                                ; uint8_t x = 3;
+	ldi r24,lo8(1)                           ; 
+	ldi r25,0                                ; int main (void)
+	ret                                      ; {
+	.size	main, .-main                     ;   x = 7;
+.global	x                                        ;   return 1;
+	.data                                    ; }
+	.type	x, @object
+	.size	x, 1
+x:
+	.byte	3
+	.ident	"GCC: (GNU) 5.4.0"
+.global __do_copy_data

20220531/variables-02.c

+#include <stdint.h>
+
+uint8_t x = 3;
+
+int main (void)
+{
+  x = 7;
+  return 1117;
+}

20220531/variables-02.s

+	.file	"variables-02.c"
+__SP_H__ = 0x3e
+__SP_L__ = 0x3d
+__SREG__ = 0x3f
+__tmp_reg__ = 0
+__zero_reg__ = 1
+	.section	.text.startup,"ax",@progbits
+.global	main
+	.type	main, @function
+main:
+/* prologue: function */
+/* frame size = 0 */
+/* stack size = 0 */
+.L__stack_usage = 0                                 ; #include <stdint.h>
+	ldi r24,lo8(7)                              ; 
+	sts x,r24                                   ; uint8_t x = 3;
+	ldi r24,lo8(93)                             ; 
+	ldi r25,lo8(4)                              ; int main (void)
+	ret                                         ; {
+	.size	main, .-main                        ;   x = 7;
+.global	x                                           ;   return 1117;
+	.data                                       ; }
+	.type	x, @object
+	.size	x, 1
+x:
+	.byte	3                                   ; 4 * 256 + 93 = 1117
+	.ident	"GCC: (GNU) 5.4.0"                  ; daher: 4 nach r25, 93 nach r24
+.global __do_copy_data
+