X-Git-Url: http://git.mutantstargoat.com/user/nuclear/?a=blobdiff_plain;f=src%2Fdos%2Fcdpmi.c;fp=src%2Fdos%2Fcdpmi.c;h=62e877a38fdd91afeff16f857ad7c9c5236c6a66;hb=4e4ac855a9d53fd7dee3d640f3ab46740b991b5c;hp=0000000000000000000000000000000000000000;hpb=f87f51babcc2d9c15e1ecaca19c26acf58292bf7;p=retroray

diff --git a/src/dos/cdpmi.c b/src/dos/cdpmi.c
new file mode 100644
index 0000000..62e877a
--- /dev/null
+++ b/src/dos/cdpmi.c
@@ -0,0 +1,102 @@
+#include <stdio.h>
+#include <i86.h>
+#include "cdpmi.h"
+
+#define LOWBUF_SIZE		8192
+#define RMSTACK_SIZE	4096
+
+static char *lowbuf, *lowfree;
+static uint16_t lowbuf_sel, lowbuf_seg;
+
+int dpmi_init(void)
+{
+	if(!(lowbuf_seg = dpmi_alloc(LOWBUF_SIZE >> 4, &lowbuf_sel))) {
+		fprintf(stderr, "DPMI init failed to allocate low memory buffer\n");
+		return -1;
+	}
+	lowbuf = (char*)((intptr_t)lowbuf_seg << 4);
+	lowfree = lowbuf + RMSTACK_SIZE;
+	return 0;
+}
+
+void dpmi_cleanup(void)
+{
+	if(!lowbuf_sel) return;
+	dpmi_free(lowbuf_sel);
+	lowbuf = 0;
+	lowbuf_sel = 0;
+	lowbuf_seg = 0;
+}
+
+void *dpmi_lowbuf(void)
+{
+	return lowfree;
+}
+
+uint16_t dpmi_alloc(unsigned int par, uint16_t *sel)
+{
+	union REGS regs = {0};
+
+	regs.w.ax = 0x100;
+	regs.w.bx = par;
+	int386(0x31, &regs, &regs);
+	if(regs.w.cflag != 0) {
+		return 0;
+	}
+	*sel = regs.w.dx;
+	return regs.w.ax;
+}
+
+void dpmi_free(uint16_t sel)
+{
+	union REGS regs = {0};
+
+	regs.w.ax = 0x101;
+	regs.w.dx = sel;
+	int386(0x31, &regs, &regs);
+}
+
+int dpmi_rmint(int inum, struct dpmi_regs *dregs)
+{
+	union REGS regs = {0};
+	struct SREGS sregs = {0};
+
+	regs.x.eax = 0x300;
+	regs.x.ebx = inum;
+	sregs.es = FP_SEG(dregs);
+	regs.x.edi = FP_OFF(dregs);
+	sregs.ss = lowbuf_seg;	/* 4k real mode stack */
+	int386x(0x31, &regs, &regs, &sregs);
+	if(regs.x.cflag != 0) {
+		return -1;
+	}
+	return 0;
+}
+
+void *dpmi_mmap(uint32_t phys_addr, unsigned int size)
+{
+	union REGS regs = {0};
+
+	regs.w.ax = 0x800;
+	regs.w.bx = phys_addr >> 16;
+	regs.w.cx = phys_addr & 0xffff;
+	regs.w.si = size >> 16;
+	regs.w.di = size & 0xffff;
+	int386(0x31, &regs, &regs);
+	if(regs.w.cflag != 0) {
+		return 0;
+	}
+
+	return (void*)(((intptr_t)regs.w.bx << 16) | (intptr_t)regs.w.cx);
+}
+
+void dpmi_munmap(void *ptr)
+{
+	union REGS regs = {0};
+	intptr_t addr = (intptr_t)ptr;
+
+	regs.w.ax = 0x801;
+	regs.w.bx = addr >> 16;
+	regs.w.cx = addr & 0xffff;
+	int386(0x31, &regs, &regs);
+}