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cc65/libsrc/em/em_load.s

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;
; Ullrich von Bassewitz, 2012-07-22
;
; unsigned char __fastcall__ em_load_driver (const char* name)
; /* Load an extended memory driver and return an error code */
.include "em-kernel.inc"
.include "em-error.inc"
.include "modload.inc"
.include "fcntl.inc"
.import pushax
.import pusha0
.import incsp2
.import _open
.import _read
.import _close
;----------------------------------------------------------------------------
; Variables
.data
ctrl: .addr _read
.res 2 ; CALLERDATA
.res 2 ; MODULE
.res 2 ; MODULE_SIZE
.res 2 ; MODULE_ID
;----------------------------------------------------------------------------
; Code
.code
.proc _em_load_driver
; Check if we do already have a driver loaded. This is an error. Do not
; touch A/X because they contain the file name.
ldy _em_drv
bne @L0
ldy _em_drv+1
beq @L1
@L0: lda #EM_ERR_INSTALLED
bne @L4
; Push the name onto the C stack and open the file. The parameter will get
; removed by open().
; ctrl.callerdata = open (name, O_RDONLY);
@L1: jsr pushax
lda #<O_RDONLY
jsr pusha0
ldy #4 ; Argument size
jsr _open
sta ctrl + MOD_CTRL::CALLERDATA
stx ctrl + MOD_CTRL::CALLERDATA+1
; if (ctrl.callerdata >= 0) {
txa
bmi @L3
; /* Load the module */
; Res = mod_load (&ctrl);
lda #<ctrl
ldx #>ctrl
jsr _mod_load
pha
; /* Close the input file */
; close (ctrl.callerdata);
lda ctrl + MOD_CTRL::CALLERDATA
ldx ctrl + MOD_CTRL::CALLERDATA+1
jsr _close
; /* Check the return code */
; if (Res == MLOAD_OK) {
pla
bne @L3
; Check the driver signature, install the driver.
; Res = em_install (ctrl.module);
lda ctrl + MOD_CTRL::MODULE
ldx ctrl + MOD_CTRL::MODULE+1
jsr _em_install
; If em_install was successful, we're done
tax
beq @L2
; The driver didn't install correctly. Remove it from memory and return the
; error code.
pha ; Save the error code
lda _em_drv
ldx _em_drv+1
jsr _mod_free ; Free the driver memory
jsr em_clear_ptr ; Clear em_drv
pla ; Restore the error code
ldx #0 ; We must return an int
@L2: rts ; Done
; Open or mod_load failed. Return an error code.
@L3: lda #<EM_ERR_CANNOT_LOAD
@L4: ldx #0
rts
.endproc