diff options
Diffstat (limited to 'firmware/fx2/common/_startup.a51.brittle')
| -rw-r--r-- | firmware/fx2/common/_startup.a51.brittle | 78 |
1 files changed, 78 insertions, 0 deletions
diff --git a/firmware/fx2/common/_startup.a51.brittle b/firmware/fx2/common/_startup.a51.brittle new file mode 100644 index 000000000..2996275cf --- /dev/null +++ b/firmware/fx2/common/_startup.a51.brittle @@ -0,0 +1,78 @@ +;;; -*- asm -*- +;;; +;;; Copyright 2003 Free Software Foundation, Inc. +;;; +;;; This file is part of GNU Radio +;;; +;;; GNU Radio is free software; you can redistribute it and/or modify +;;; it under the terms of the GNU General Public License as published by +;;; the Free Software Foundation; either version 3, or (at your option) +;;; any later version. +;;; +;;; GNU Radio is distributed in the hope that it will be useful, +;;; but WITHOUT ANY WARRANTY; without even the implied warranty of +;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +;;; GNU General Public License for more details. +;;; +;;; You should have received a copy of the GNU General Public License +;;; along with GNU Radio; see the file COPYING. If not, write to +;;; the Free Software Foundation, Inc., 51 Franklin Street, +;;; Boston, MA 02110-1301, USA. + + +;;; The default external memory initialization provided by sdcc is not +;;; appropriate to the FX2. This is derived from the sdcc code, but uses +;;; the FX2 specific _MPAGE sfr. + + + .area XISEG (XDATA) ; the initialized external data area + .area XINIT (CODE) ; the code space consts to init XISEG + .area XSEG (XDATA) ; zero initialized xdata + .area USBDESCSEG (XDATA); usb descriptors + + + ;; BIG TIME KLUDGE! + ;; Look at usrp_main.rst and count the bytes from our + ;; "normal return location" to the first instruction following + ;; the comment: "_mcs51_getRAMCLEAR () start" + + INSTRUCTION_BYTES_TO_SKIP = 0x29 ; valid for sdcc 2.4.0 + + + .area CSEG (CODE) + + ;; sfr that sets upper address byte of MOVX using @r0 or @r1 + _MPAGE = 0x0092 + +__sdcc_external_startup:: +; _mcs51_genXINIT() start + mov r1,#l_XINIT + mov a,r1 + orl a,#(l_XINIT >> 8) + jz 00003$ + mov r2,#((l_XINIT+255) >> 8) + mov dptr,#s_XINIT + mov r0,#s_XISEG + mov _MPAGE,#(s_XISEG >> 8) +00001$: clr a + movc a,@a+dptr + movx @r0,a + inc dptr + inc r0 + cjne r0,#0,00002$ + inc _MPAGE +00002$: djnz r1,00001$ + djnz r2,00001$ + mov _MPAGE,#0xFF +00003$: + + ;; Danger! Total KLUDGE! + ;; We pop the return address, add a magic number to it + ;; then jump to that address. Believe it or not, this + ;; looks like the least kludgy way to handle this, + ;; short of patching the compiler... + + pop dph + pop dpl + mov a,#INSTRUCTION_BYTES_TO_SKIP + jmp @a+dptr |