From: John Tsiombikas <nuclear@member.fsf.org>
Date: Tue, 12 Nov 2019 11:09:31 +0000 (+0200)
Subject: start writing new VBE routines
X-Git-Url: http://git.mutantstargoat.com/user/nuclear/?p=dosdemo;a=commitdiff_plain;h=2c4602e53eaab44272ea5cd62667c939e6d2f61b

start writing new VBE routines
---

diff --git a/src/dos/cdpmi.h b/src/dos/cdpmi.h
index cdfd2f7..4fc2c30 100644
--- a/src/dos/cdpmi.h
+++ b/src/dos/cdpmi.h
@@ -6,7 +6,9 @@
 #endif
 
 #include "inttypes.h"
+#include "util.h"
 
+#pragma pack (push, 1)
 struct dpmi_regs {
 	uint32_t edi, esi, ebp;
 	uint32_t reserved;
@@ -14,7 +16,8 @@ struct dpmi_regs {
 	uint16_t flags;
 	uint16_t es, ds, fs, gs;
 	uint16_t ip, cs, sp, ss;
-};
+} PACKED;
+#pragma pack (pop)
 
 uint16_t dpmi_alloc(unsigned int par, uint16_t *sel);
 void dpmi_free(uint16_t sel);
@@ -27,6 +30,9 @@ void dpmi_munmap(void *addr);
 		"mov ax, 0x100" \
 		"int 0x31" \
 		"mov [edi], dx" \
+		"jnc alloc_skip_err" \
+		"xor ax, ax" \
+		"alloc_skip_err:" \
 		value[ax] \
 		parm[ebx][edi];
 
diff --git a/src/dos/vbe.c b/src/dos/vbe.c
new file mode 100644
index 0000000..d5d75df
--- /dev/null
+++ b/src/dos/vbe.c
@@ -0,0 +1,28 @@
+#include "vbe.h"
+#include "cdpmi.h"
+
+int vbe_getinfo(struct vbe_info *info)
+{
+	void *lowbuf;
+	uint16_t seg, sel;
+	struct dpmi_regs regs = {0};
+
+	if(!(seg = dpmi_alloc(512 / 16, &sel))) {
+		return -1;
+	}
+
+	regs.eax = 0x4f00;
+	regs.es = seg;
+	regs.edi = 0;
+	dpmi_int(0x10, &regs);
+
+	if(regs.eax & 0xff00) {
+		dpmi_free(sel);
+		return -1;
+	}
+
+	lowbuf = (void*)((uint32_t)seg << 4);
+	memcpy(info, lowbuf, sizeof info);
+	dpmi_free(sel);
+	return 0;
+}
diff --git a/src/dos/vbe.h b/src/dos/vbe.h
new file mode 100644
index 0000000..73df02f
--- /dev/null
+++ b/src/dos/vbe.h
@@ -0,0 +1,38 @@
+#ifndef VBE_H_
+#define VBE_H_
+
+#include "inttypes.h"
+#include "util.h"
+
+#pragma pack (push, 1)
+struct vbe_info {
+	char sig[4];
+	uint16_t ver;
+	char *oem_name;
+	uint32_t caps;
+	uint16_t *modes;
+	uint16_t oem_ver;
+	char *vendor;
+	char *product;
+	char *revstr;
+	uint16_t accel_ver;
+	uint16_t accel_modes;
+} PACKED;
+#pragma pack (pop)
+
+enum {
+	VBE_8BIT_DAC	= 0x01,
+	VBE_NON_VGA		= 0x02,
+	VBE_DAC_BLANK	= 0x04,
+	VBE_STEREO		= 0x08,	/* ? */
+	VBE_ACCEL		= 0x08,
+	VBE_STEREO_VESA	= 0x10,	/* ? */
+	VBE_MUSTLOCK	= 0x10,
+	VBE_HWCURSOR	= 0x20,
+	VBE_HWCLIP		= 0x40,
+	VBE_TRANSP_BLT	= 0x80
+};
+
+int vbe_getinfo(struct vbe_info *info);
+
+#endif	/* VBE_H_ */
diff --git a/src/util.h b/src/util.h
index 76dd044..6d869eb 100644
--- a/src/util.h
+++ b/src/util.h
@@ -5,12 +5,15 @@
 
 #ifdef __GNUC__
 #define INLINE __inline
+#define PACKED __attribute__((packed))
 
 #elif defined(__WATCOMC__)
 #define INLINE __inline
+#define PACKED
 
 #else
 #define INLINE
+#define PACKED
 #endif
 
 /* fast conversion of double -> 32bit int