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collapseos/emul/forth/glue0.asm
2020-03-19 17:26:45 -04:00

40 lines
873 B
NASM

; RAM disposition
;
; Because this glue code also serves stage0 which needs HERE to start right
; after the code, we have a peculiar RAM setup here: it lives at the very end
; of the address space, just under RS_ADDR at 0xf000
; Warning: The offsets of native dict entries must be exactly the same between
; glue0.asm and glue1.asm
.equ RAMSTART 0xe800
.equ HERE 0xe700 ; override, in sync with stage1.c
.equ CURRENT 0xe702 ; override, in sync with stage1.c
.equ HERE_INITIAL CODE_END ; override
.equ STDIO_PORT 0x00
jp init
.equ GETC emulGetC
.equ PUTC emulPutC
.inc "forth.asm"
init:
di
; setup stack
ld sp, 0xffff
call forthMain
halt
emulGetC:
; Blocks until a char is returned
in a, (STDIO_PORT)
cp a ; ensure Z
ret
emulPutC:
out (STDIO_PORT), a
ret
.dw 0 ; placeholder used in glue1.
CODE_END:
.out $ ; should be the same as in glue1