start writting examples

src/1_8.asm

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+; assembly that shows how to return values to a
+; a C function
+
+    option casemap:none
+
+; constants
+nl      =       10
+maxlen  =       256
+
+    .data
+
+title_str   byte        "Listing 1-8", 0
+prompt      byte        "Enter a string: ", 0
+fmt_string  byte        "User entered: '%s'", nl, 0
+
+; make `maxlen` copies/duplicates of size byte, each uinitialized
+input       byte maxlen dup (?)
+
+

src/c.cpp

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+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+
+extern "C" 
+{
+    void asm_main(void);
+
+
+    char *get_title(void);
+
+    int readline(char* dest, int maxlen);
+}
+
+int readline(char *dest, int maxlen) 
+{
+    char *result = fgets(dest, maxlen, stdin);
+    if (results != NULL) {
+        int len = strlen(result);
+        if (len > 0) {
+            dest[len - 1] = 0;
+        }
+        return(len);
+    }
+
+    return(-1) // an error occured
+}
+
+int main(void)
+{
+
+    try {
+        char *title = get_title();
+        printf("calling %s\n", title);
+        asm_func();
+        printf("%s terminated\n", title);
+
+    } catch(...) {
+        printf("an error occured!")
+    }
+}

src/hello.asm

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+; a hello world program using printf from C
+
+    option casemap:none
+
+    .data 
+
+format_string byte "Hello from asm world!", 10, 0 
+
+    .code
+
+    externdef printf:proc
+
+    public asm_func
+
+asm_func proc
+    
+    sub     rsp, 56
+    lea     rcx, format_string
+    call    printf
+    add     rsp, 56
+
+    ret
+
+asm_func endp
+
+    end
+

src/main.cpp

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+#include <stdio.h>
+
+extern "C" 
+{
+    void asm_func(void);
+};
+
+int main(void) 
+{
+    printf("calling asm main\n");
+    asm_func();
+    printf("return from asm main\n");
+}

src/program.asm

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+; comments start with a colon
+
+
+    .CODE
+
+    option casemap:none
+
+    public asm_func
+
+asm_func PROC
+
+    ret     ; returns to the caller
+
+asm_func ENDP
+
+    END
+