113 lines
2.8 KiB
NASM
113 lines
2.8 KiB
NASM
; ***************************************************************************
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; copyright : (C) 2025 by Martin Preuss
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; email : martin@libchipcard.de
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;
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; ***************************************************************************
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; * This file is part of the project "AqHome". *
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; * Please see toplevel file COPYING of that project for license details. *
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; ***************************************************************************
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; ---------------------------------------------------------------------------
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; @macro m_fixedbuf_init
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;
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; @param X pointer to start of buffers
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; @param %0 constant maxBytes per buffer (including statusbyte in front)
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; @param %1 constant maxBuffers
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; @clobbers r16, r17, X
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.macro m_fixedbuf_init
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ldi r17, @1
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clr r16
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l_loop:
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st X, r16 ; unused
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adiw xh:xl,@0
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dec r17
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brne l_loop
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.endmacro
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; @end
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; ---------------------------------------------------------------------------
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; @macro m_fixedbuf_reserve
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;
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; @return CFLAG set if buffer available, cleared otherwise
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; @return r16 buffer num
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; @return X pointer to start of buffer
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; @param X pointer to start of buffers
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; @param %0 constant maxBytes per buffer (including statusbyte in front)
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; @param %1 constant maxBuffers
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; @clobbers r16, r17, X
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.macro m_fixedbuf_reserve
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clr r17 ; loop var: current buffer num
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l_loop:
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ld r16, X
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tst r16
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breq l_foundfree
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adiw xh:xl, @0
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inc r17
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cpi r17, @1
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brcs l_loop
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rjmp l_end ; use cleared CFLAG
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l_foundfree:
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ldi r16, 0x80 ; mark as used
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st X, r16
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mov r16, r17
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sec ; set CFLAG, return bufnum in r16, pointre in X
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l_end:
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.endmacro
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; @end
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; ---------------------------------------------------------------------------
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; @macro m_fixedbuf_release
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;
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; @param X pointer to start of buffers
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; @param %0 constant maxBytes per buffer (including statusbyte in front)
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; @param %1 constant maxBuffers
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; @clobbers r16
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.macro m_fixedbuf_release
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clr r16
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st X, r16
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.endmacro
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; @end
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; ---------------------------------------------------------------------------
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; @macro m_fixedbuf_locate
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;
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; use this routine only if you can't easily calculate the offset of the buffer
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; (e.g. by using shift operations for calculation)
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;
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; @return CFLAG set if buffer found, cleared otherwise
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; @return X pointer to start of located buffer (points to the statusbyte in front)
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; @param r16 buffer num
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; @param X pointer to start of buffers
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; @param %0 constant maxBytes per buffer
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; @param %1 constant maxBuffers
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; @clobbers r16, X
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.macro m_fixedbuf_locate
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cpi r16, @1
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brcc l_end ; idx out of range, use cleared CFLAG
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tst r16 ; doesn't change CFLAG which is set from CPI above
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breq l_end ; buffer 0, return start of buffers
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l_loop:
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adiw xh:xl, @0
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dec r16
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brne l_loop
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sec
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l_end:
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.endmacro
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; @end
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