diff options
| -rw-r--r-- | src/romlayout.S | 44 |
1 files changed, 28 insertions, 16 deletions
diff --git a/src/romlayout.S b/src/romlayout.S index 1bbdd9c..556c4b7 100644 --- a/src/romlayout.S +++ b/src/romlayout.S @@ -70,12 +70,11 @@ transition32: popl %eax retl -// Call a 16bit function from 32bit mode. -// %eax = address of struct bregs -// Clobbers: %e[bcd]x, %e[ds]i, flags, segment registers, idt/gdt - DECLFUNC __call16_from32 - .global __call16big_from32 -__call16_from32: +// Place CPU into 16bit mode from 32bit mode. +// Clobbers: flags, segment registers, cr0, idt/gdt + DECLFUNC transition16 + .global transition16big +transition16: pushl %eax // restore data segment limits to 0xffff @@ -96,7 +95,7 @@ __call16_from32: // Jump to 16bit mode ljmpw $SEG32_MODE16_CS, $1f -__call16big_from32: +transition16big: pushl %eax movl $SEG32_MODE16BIG_DS, %eax @@ -131,13 +130,7 @@ __call16big_from32: movw %ax, %ss // Assume stack is in segment 0 popl %eax - - // Make call. - calll __call16 - - // Return via transition32 - jmp transition32 - + retl // Call a 16bit function from 16bit mode with a specified cpu register state // %eax = address of struct bregs @@ -195,6 +188,25 @@ __call16: retl +// Call a 16bit function from 32bit mode. +// %eax = address of struct bregs +// Clobbers: %e[bcd]x, %e[ds]i, flags, segment registers, idt/gdt + DECLFUNC __call16_from32 + .global __call16big_from32 + .code32 +__call16_from32: + pushl $1f + jmp transition16 +__call16big_from32: + pushl $1f + jmp transition16big + + // Make call. + .code16gcc +1: calll __call16 + // Return via transition32 + jmp transition32 + // IRQ trampolines .macro IRQ_TRAMPOLINE num DECLFUNC irq_trampoline_0x\num @@ -285,7 +297,7 @@ entry_pmm: pushw %ds movw %ss, %cx // Move %ss to %ds movw %cx, %ds - lea 28(%esp), %eax // %eax points to start of args + leal 28(%esp), %eax // %eax points to start of args calll handle_pmm movw %ax, 12(%esp) // Modify %ax:%dx to return %eax shrl $16, %eax @@ -319,7 +331,7 @@ entry_pnp_real: pushw %ds movw %ss, %cx // Move %ss to %ds movw %cx, %ds - lea 28(%esp), %eax // %eax points to start of u16 args + leal 28(%esp), %eax // %eax points to start of u16 args calll handle_pnp movw %ax, 12(%esp) // Modify %eax to return %ax popw %ds |