| 33,12 → 33,14 |
|---|
| #include "rmodinit.h" |
| |
| |
| /* returns segment where rmod is installed */ |
| unsigned short rmod_install(unsigned short envsize) { |
| /* returns far pointer to rmod's settings block on success */ |
| struct rmod_props far *rmod_install(unsigned short envsize) { |
| char far *myptr, far *mcb; |
| unsigned short far *owner; |
| const unsigned short sizeof_rmodandprops_paras = rmod_len + sizeof(struct rmod_props) + 15 / 16; |
| unsigned int rmodseg = 0xffff; |
| unsigned int envseg = 0; |
| struct rmod_props far *res = NULL; |
| |
| /* read my current env segment from PSP */ |
| _asm { |
| 52,6 → 54,10 |
|---|
| } |
| |
| /* printf("original (PSP) env buffer at %04X\r\n", envseg); */ |
| |
| /* if envseg is zero, then enforce our own one (MSDOS 5 does not provide a default env) */ |
| if ((envseg == 0) && (envsize == 0)) envsize = 256; |
| |
| /* if custom envsize requested, convert it to number of paragraphs */ |
| if (envsize != 0) { |
| envsize += 15; |
| 79,7 → 85,7 |
|---|
| int 0x21 |
| /* ask for a memory block and save the given segment to rmodseg */ |
| mov ah, 0x48 |
| mov bx, (rmod_len + 15) / 16 |
| mov bx, sizeof_rmodandprops_paras |
| int 0x21 |
| jc ALLOC_FAIL |
| mov rmodseg, ax |
| 105,7 → 111,7 |
|---|
| |
| if (rmodseg == 0xffff) { |
| outputnl("malloc error"); |
| return(0xffff); |
| return(NULL); |
| } |
| |
| /* copy rmod to its destination */ |
| 124,6 → 130,18 |
|---|
| *owner = rmodseg; |
| _fmemcpy(mcb + 8, "SVARENV", 8); |
| |
| /* if env block is newly allocated, fill it with a few NULLs */ |
| if (envsize != 0) { |
| owner = MK_FP(envseg, 0); |
| owner[0] = 0; |
| owner[1] = 0; |
| } |
| |
| /* prepare result (rmod props) */ |
| res = MK_FP(rmodseg, rmod_len); |
| _fmemset(res, 0, sizeof(*res)); |
| res->rmodseg = rmodseg; |
| |
| /* write env segment to rmod buffer */ |
| owner = MK_FP(rmodseg, RMOD_OFFSET_ENVSEG); |
| *owner = envseg; |
| 179,13 → 197,13 |
|---|
| pop ax |
| } |
| |
| return(rmodseg); |
| return(res); |
| } |
| |
| |
| /* look up my parent: if it's rmod then return its segment, |
| * otherwise return 0xffff */ |
| unsigned short rmod_find(void) { |
| /* look up my parent: if it's rmod then return a ptr to its props struct, |
| * otherwise return NULL */ |
| struct rmod_props far *rmod_find(void) { |
| unsigned short *parent = (void *)0x0C; /* parent's seg in PSP[Ch] ("prev. int22 handler") */ |
| unsigned short far *ptr; |
| const unsigned short sig[] = {0x1983, 0x1985, 0x2017, 0x2019}; |
| 192,9 → 210,9 |
|---|
| unsigned char i; |
| /* is it rmod? */ |
| ptr = MK_FP(*parent, 0); |
| for (i = 0; i < 4; i++) if (ptr[i] != sig[i]) return(0xffff); |
| for (i = 0; i < 4; i++) if (ptr[i] != sig[i]) return(NULL); |
| /* match successfull (rmod is my parent) */ |
| return(*parent); |
| return(MK_FP(*parent, rmod_len)); |
| } |
| |
| |