Added an untested implementation of snprintf.

git-svn-id: svn://svn.cc65.org/cc65/trunk@4246 b7a2c559-68d2-44c3-8de9-860c34a00d81

diff --git a/libsrc/common/Makefile b/libsrc/common/Makefile
index 0c6d768517494d2ad44f47309c4ce37bc60e7ac8..df3c97277d4e405f89752b7bd6cebe2c4ca672fc 100644 (file)
--- a/libsrc/common/Makefile
+++ b/libsrc/common/Makefile
@@ -156,6 +156,7 @@ S_OBJS =    _cwd.o          \
                setjmp.o        \
                 signal.o        \
                 sigtable.o      \
+                snprintf.o      \
                sprintf.o       \
                sscanf.o        \
                strcat.o        \

diff --git a/libsrc/common/snprintf.s b/libsrc/common/snprintf.s
new file mode 100644 (file)
index 0000000..33ce4b1
--- /dev/null
+++ b/libsrc/common/snprintf.s
@@ -0,0 +1,69 @@
+;
+; int snprintf (char* buf, size_t size, const char* Format, ...);
+;
+; Ullrich von Bassewitz, 2009-09-26
+;
+
+       .export         _snprintf
+       .import         pushax, addysp, decsp6, _vsnprintf
+       .importzp       sp, ptr1
+
+       .macpack        generic
+
+; ----------------------------------------------------------------------------
+; Data
+
+.bss
+
+ParamSize:     .res    1               ; Number of parameter bytes
+
+; ----------------------------------------------------------------------------
+; Code
+
+.code
+
+
+_snprintf:
+       sty     ParamSize               ; Number of param bytes passed in Y
+
+; We have to push buf/size/format, both in the order they already have on stack.
+; To make this somewhat more efficient, we will create space on the stack and
+; then do a copy of the complete block instead of pushing each parameter
+; separately. Since the size of the arguments passed is the same as the size
+; of the fixed arguments, this will allow us to calculate the pointer to the
+; fixed size arguments easier (they're just ParamSize bytes away).
+
+       jsr     decsp6
+
+; Calculate a pointer to the Format argument
+
+       lda     ParamSize
+       add     sp
+       sta     ptr1
+       ldx     sp+1
+       bcc     @L1
+       inx
+@L1:   stx     ptr1+1
+
+; Now copy buf/size/format
+
+       ldy     #6-1
+@L2:   lda     (ptr1),y
+       sta     (sp),y
+       dey
+       bpl     @L2
+
+; Load va_list (last and __fastcall__ parameter to vsprintf)
+
+       lda     ptr1
+       ldx     ptr1+1
+
+; Call vsnprintf
+
+       jsr     _vsnprintf
+
+; Cleanup the stack. We will return what we got from vsprintf
+
+       ldy     ParamSize
+       jmp     addysp
+